Airworthiness Standards; Systems and Equipment Proposals Based on European Joint Aviation Requirements Proposals; Proposed Rule DEPARTMENT OF TRANSPORTATION

SUMMARY: This document proposes changes to the systems and equipment

airworthiness standards for normal, utility, acrobatic, and commuter

category airplanes. These proposals arise from the joint effort of the

Federal Aviation Administration (FAA) and the European Joint Aviation

Authorities (JAA) to harmonize the Federal Aviation Regulations (FAR)

and the Joint Aviation Requirements (JAR) for airplanes that will be

certificated in these categories. The proposed changes would provide

nearly uniform systems and equipment airworthiness standards for

airplanes certificated in the United States under 14 CFR part 23 (part

23) and in the JAA countries under Joint Aviation Requirements 23 (JAR

23), thereby simplifying airworthiness approval for import and export

purposes.

DATES: Comments must be submitted on or before November 21, 1994.

ADDRESSES: Comments on this document should be mailed in triplicate to:

Federal Aviation Administration, Office of the Chief Counsel,

Attention: Rules Docket (AGC-200), Docket No. 27806, 800 Independence

Avenue SW., Washington, DC 20591.

Comments delivered must be marked Docket No. 27806. Comments may be

inspected in Room 915G weekdays between 8:30 a.m. and 5 p.m., except on

Federal holidays.

In addition, the FAA is maintaining an information docket of

comments in the Office of the Assistant Chief Counsel, ACE-7, Federal

Aviation Administration, Central Region, 601 East 12th Street, Kansas

City, Missouri 64106. Comments in the duplicate information docket may

be inspected in the Office of the Assistant Chief Counsel weekdays,

except Federal holidays, between the hours of 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Earsa Tankesley, ACE-112, Small

Airplane Directorate, Aircraft Certification Service, Federal Aviation

Administration, 601 East 12th Street, Kansas City, Missouri 64106;

telephone (816) 426-5688.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the

proposed rule by submitting such written data, views, or arguments as

they may desire. Comments relating to the environmental, energy, or

economic impact that might result from adopting the proposals in this

notice are also invited. Substantive comments should be accompanied by

cost estimates. Comments should identify the regulatory docket or

notice number and should be submitted in triplicate to the Rules Docket

address specified above. All comments received on or before the

specified closing date for comments will be considered by the

Administrator before taking action on this proposed rulemaking. The

proposals contained in this notice may be changed in light of comments

received. All comments received will be available, both before and

after the closing date for comments, in the Rules Docket for

examination by interested persons. A report summarizing each FAA-public

contact concerned with the substance of this proposal will be filed in

the docket. Commenters wishing the FAA to acknowledge receipt of their

comments submitted in response to this notice must include a

preaddressed, stamped postcard on which the following statement is

made: ``Comments to Docket No. 27806.'' The postcard will be date

stamped and returned to the commenter.

Availability of NPRM

Any person may obtain a copy of this NPRM by submitting a request

to the Federal Aviation Administration, Office of Public Affairs,

Attention: Public Inquiry Center, APA-200, 800 Independence Avenue,

SW., Washington, DC 20591, or by calling (202) 267-3484. Communications

must identify the notice number of this NPRM.

Persons interested in being placed on the mailing list for future

NPRM's should request, from the above office, a copy of Advisory

Circular No. 11-2A, Notice of Proposed Rulemaking Distribution System,

which describes the application procedure.

Background

At the June 1990 meeting of the JAA Council (consisting of JAA

members from European countries) and the FAA, the FAA Administrator

committed the FAA to support the harmonization of the FAR with the JAR

being developed for use by the European authorities who are members of

the JAA. In response to this commitment, the FAA Small Airplane

Directorate established an FAA Harmonization Task Force to work with

the JAR 23 Study Group to harmonize part 23 and the proposed JAR 23.

The General Aviation Manufacturers Association (GAMA) also established

a JAR 23/part 23 Committee to provide technical assistance in this

effort.

Following a review of the first draft of proposed JAR 23, members

of the FAA Harmonization Task Force and the GAMA Committee met in

Brussels, Belgium for the October 1990 meeting of the JAR 23 Study

Group. Representatives from the Association Europeene des

Constructeures de Material Aerospatial (AECMA), an organization of

European airframe manufacturers, also attended. The main agenda item

for this meeting was the establishment of procedures to accomplish

harmonization of the airworthiness standards for normal, utility, and

acrobatic category airplanes. The JAA had decided that its initial

rulemaking effort should be limited to these three categories and that

commuter category airworthiness standards should be addressed

separately.

After that meeting, technical representatives from each of the four

organizations (GAMA, AECMA, FAA and JAA) met to resolve differences

between the proposed JAR and part 23. This portion of the harmonization

effort involved a number of separate meetings of specialists in the

flight, airframe, powerplant, and systems disciplines. These meetings

showed that harmonization would require revisions to both part 23 and

the proposed JAR 23.

Near the end of the effort to harmonize the normal, utility, and

acrobatic category airplane airworthiness standards, the JAA requested

and received recommendations from its member countries on proposed

airworthiness standards for commuter category airplanes. The JAA and

the FAA held specialist and study group meetings to discuss these

recommendations, which resulted in proposals to revise portions of the

part 23 commuter category airworthiness standards.

Unlike the European rules, where commuter category airworthiness

standards are separate, for U.S. rulemaking, it is advantageous to

adopt normal, utility, acrobatic, and commuter category airworthiness

standards simultaneously, since commuter category airworthiness

standards are already contained in part 23. Accordingly, this NPRM

proposes to revise the systems and equipment airworthiness standards

for all part 23 airplanes.

During the part 23 harmonization effort, the FAA established an

Aviation Rulemaking Advisory Committee (ARAC) (56 FR 2190, January 22,

1991), which held its first meeting on May 23, 1991. The ARAC on

General Aviation and Business Airplane (GABA) Issues was established at

that meeting to provide advice and recommendations to the Director,

Aircraft Certification Service, FAA, regarding the airworthiness

standards in part 23 as well as related provisions of parts 91 and 135

of the regulations.

The FAA announced, on June 2-5, 1992, at the JAA/FAA Harmonization

Conference in Toronto, Ontario, Canada, that it would consolidate

within the ARAC structure an ongoing objective to ``harmonize'' the JAR

and the FAR. Coinciding with that announcement, the FAA assigned the

ARAC on GABA Issues those rulemaking projects related to JAR/part 23

harmonization that were in final coordination between the JAA and the

FAA. The harmonization process included the intention to present the

results of JAA/FAA coordination to the public as NPRM's. Subsequently,

the ARAC on GABA Issues established an ARAC-JAR 23 Study Group.

The JAR 23 Study Group made recommendations to the ARAC on GABA

Issues concerning the FAA disposition of the rulemaking issues

coordinated between the JAA and the FAA. The draft NPRMs previously

prepared by the FAA harmonization team were made available to the

harmonization working group to assist them in their effort.

A notice of the formation of the JAR 23 Harmonization Working Group

was published on November 30, 1992 (57 FR 56626). The group held its

first meeting on February 2, 1993. These efforts resulted in the

proposals for systems and equipment airworthiness standards contained

in this notice. The ARAC on GABA Issues agreed with these proposals.

The FAA received unsolicited comments from the JAA dated January

20, 1994, concerning issues that were left unresolved with the JAR 23

Study Group. The JAR/FAR 23 Harmonization Working Group did not address

some of the unresolved issues because the JAA had not yet reached

positions on those issues. Unresolved issues will be dealt with at

future FAR/JAR Harmonization meetings. With respect to other issues

unresolved by the JAR 23 Study Group, the JAR/FAR 23 Harmonization

Working Group recommendations did not reflect harmonization, but

reflected the technical discussion of the merits of each issue that had

been thoroughly debated at the JAR/FAR 23 Harmonization meetings. (The

Working Group Chairperson had been present at the Harmonization

meetings.) The JAA comments have been placed in the docket for this

proposal, and will be considered along with those received during the

comment period.

Following completion of these harmonization efforts, the FAA

determined that the proposed revisions to part 23 were too numerous for

a single NPRM. The FAA decided to simplify the issues by issuing four

NPRM's. These NPRM's address the airworthiness standards in the

specific areas of systems and equipment, powerplant, flight, and

airframe. These NPRM's propose changes in all seven subparts of part

23. Since there is some overlap, interested persons are advised to

review all four NPRM's to identify all proposed changes to a particular

section.

Discussion of Proposals

Section 23.677 Trim Systems

Proposed revised Sec. 23.677(a) would clarify the need to mark the

lateral and directional trim indicators with the neutral trim position.

Since trim indicators on most airplanes are currently marked with the

neutral position of the trimming device, this proposal would

standardize the cockpit markings for all airplanes.

Revised paragraph (a) would also add a requirement for the pitch

trim indicator to be marked with the proper pitch trim range for the

takeoff of the airplane. Some takeoff accidents, including some

involving fatalities, have occurred because the pitch trim was not set

to the proper range needed for the airplane takeoff. Because of this

accident experience, most of the current airplane manufacturers mark

the pitch trim indicator with the pitch trim range for takeoff.

Therefore, the proposed marking requirement would not have a

significant impact on future airplane designs and would ensure that the

markings needed for a safe takeoff are provided for the pilots' use.

Section 23.691 Artificial Stall Barrier System

This proposed new section would provide standards for stall barrier

systems if a stall barrier is necessary to show compliance with

Sec. 23.201(c).

The requirements of Sec. 23.201(c) provide criteria for the in-

flight demonstration of wings level stall. The requirements also

specify the means of identifying when a stall has occurred. Amendment

No. 23-45 (58 FR 42136, August 6, 1993) revised Sec. 23.201(c) by

adding the activation of an artificial stall barrier as an acceptable

means of identifying when a stall has occurred.

As the technology of airplane designs improved and engines with

increased power became available, airplanes were developed that did not

meet the older wings level stall requirement of Sec. 23.201.

Consequently, these airplanes were equipped with an artificial stall

barrier that moved the airplane elevator controls and caused a nose

down pitching motion similar to the pitching motion of airplanes that

meet the wings level stall requirement of Sec. 23.201. The manufacturer

selected the airspeed where this pitching motion occurred and flight

testing established compliance with the other flight regulations at

airspeeds above the speed selected for the push. These stall barrier

systems are commonly called ``stick pushers.'' Such systems have been

accepted for compliance with Sec. 23.201 under the equivalent safety

provisions of Sec. 21.21(b)(1), since they provide a pitch motion that

is equivalent to that experienced during stalls of airplanes that meet

the stall requirements of Sec. 23.201. Appropriate compliance with

other applicable requirements of part 23 has been established by other

design characteristics of the stall barrier system.

The provisions of the proposed new section are based on system

design characteristics necessary to ensure the safe operation of

previously approved stall barrier systems. The proposed section also

requires such systems to include provisions to prevent unwanted

activation of the stall barrier systems. This is necessary to ensure

that such systems do not cause downward pitching motions at higher

airspeeds when such pitching could be unsafe.

The proposed sections would basically codify those provisions that

have been found necessary for approving stick pusher systems under the

equivalent safety requirements of Sec. 21.21(b)(1). Therefore, in

effect, no new requirements would be added by this proposed amendment.

The proposed new section would be applicable only to airplanes with

flight characteristics that need an artificial stall barrier system to

ensure safe operation of that airplane. Including provision for the

installation of an optional stick pusher system would relieve the

manufacturer of the financial burden that would be needed to redesign

the airplane so that it would meet the wings level stall requirements.

Section 23.697 Wing Flap Controls

Proposed new Sec. 23.697(c) would provide safety standards for the

wing flap control lever designs installed in airplanes that use wing

flap settings other than fully retracted when showing compliance with

Sec. 23.145. This revision is needed to ensure that the flap settings,

which establish the safe operation of the airplane, can be positively

selected.

Section 23.701 Flap Interconnection

Section 23.701 (a)(1) and (a)(2) would be revised to clarify the

requirements for flap systems installed on part 23 airplanes. Following

the revision of Sec. 23.701, as adopted by Amendment No. 23-42 (56 FR

353, January 3, 1991), the FAA discovered that the new requirements

could be interpreted in a way that was not intended and that this

interpretation could result in approval of airplanes with unsafe flight

characteristics in the event of flap failure. To clarify the intent of

the requirements, the FAA issued on March 14, 1991, a policy letter to

all aircraft certification offices that provided guidance for the

correct application of the requirements.

Since then, the FAA has reexamined the requirements and determined

that Sec. 23.701 (a)(1) and (a)(2) need to be revised to ensure that a

failure of the flap system would not create an asymmetric flap

configuration that could result in an unsafe flight condition.

Therefore, Sec. 23.701 (a)(1) and (a)(2) would be revised to clarify

that one of the following would apply:

(1) The moveable flap surfaces must be synchronized by a mechanical

interconnection or by an approved equivalent means, that is independent

of the flap drive system.

(2) The wing flap system must be designed so that any failures of

the flap system that would result in an unsafe flight characteristic of

the airplane, such as flap asymmetry, is extremely improbable.

These revisions would ensure that a failure of the flap drive

systems will not result in a flap asymmetry configuration.

Section 23.703 Takeoff Warning System

This proposed new section would require a takeoff warning system on

some commuter category airplanes. The requirement would be applicable

if the flight evaluation showed that an unsafe takeoff condition would

result if lift devices or longitudinal trim devices are set to any

position outside the approved takeoff range. If the evaluation shows

that no unsafe condition would result at any setting of these devices,

a takeoff warning system would not be required. For those airplanes on

which a warning system must be installed, the proposal would provide

requirements for the installation of the system.

Section 23.723 Shock Absorption Tests

Paragraph (b) of this section would be revised by changing the word

``reserved'' in the phrase ``reserved energy absorption capacity'' to

``reserve.''

Section 23.729 Landing Gear Extension and Retraction System

This proposal would revise Sec. 23.729(e) to clarify that a landing

gear indicator is required for each gear. The last sentence of current

Sec. 23.729(e) would also be removed. This sentence, which states that

the switches may be located where they are operated by the actual

landing gear locking latch or device, is advisory material and should

not be included in the requirements. If future guidance is needed to

identify acceptable switch locations, Advisory Circular 23.701-1 will

be revised to include that information.

This proposal would also add a new Sec. 23.729(g) requiring that if

the landing gear bay is used as the location for equipment other than

landing gear, the equipment must be designed and installed to minimize

damage. On larger airplanes, such as the commuter category, a primary

cause of damage to such equipment would be tire burst. In addition,

service history has shown that rocks, water, and slush enter the

landing gear bay and cause damage. The equipment on any size airplane

should be protected from damage by such external sources.

Section 23.735 Brakes

Section 23.735(a) would be revised to state plainly that wheel

brakes must be provided. A proposed new Sec. 23.735(c) would require

the brake system to be designed so that the brake manufacturer's

specified brake pressures are not exceeded during the landing distance

determination required by Sec. 23.75.

Proposed new Sec. 23.735(e), applicable to commuter category

airplanes, would require establishing the minimum rejected takeoff

brake kinetic energy capacity rating of each main wheel brake assembly.

Section 23.45 provides that the determination of the accelerate-stop

distance for commuter category airplanes be made in accordance with the

applicant's procedures for operation in service. The proposed

requirement is needed to ensure that the brakes will perform safely

under accelerate-stop conditions.

Section 23.745 Nose/Tail Wheel Steering

Proposed new Sec. 23.745 would provide requirements that apply if

nose/tail-wheel steering is installed. Advanced airplane design

technology, along with the need to safely control the airplane when it

is being operated on increasingly congested airports, has resulted in

several small airplanes being equipped with systems for ground steering

only.

The proposed new section would not require the installation of a

system for ground steering, but it would add requirements to define how

such a system should function if one is installed. It would also

require the steering system to be designed so that it will not

interfere with any installed landing gear retraction and extension

system.

Section 23.775 Windshields and Windows

Section 23.775(a) would be revised to state that internal glass

panels of windshields and windows must be constructed of a

nonsplintering material, such as nonsplintering glass. Currently

Sec. 23.775(a) requires nonsplintering safety glass only. A

nonsplintering material must be used to protect pilots from injury.

While nonsplintering glass is an acceptable standard, other

nonsplintering materials would be allowed under the proposal.

Section 23.775(c) would be revised to clarify that it applies to

pressurized airplanes if certification for operation up to and

including 25,000 feet is requested. This would not be a substantive

change. It has always applied to such airplanes but is not as directly

stated in the current rule as it would be in the proposed rule. Current

Sec. 23.775(e), which is being redesignated as Sec. 23.775(d) by this

notice without change, provides requirements for airplanes that are

certified for operations above 25,000 feet. This revision of paragraph

(c) and redesignation of paragraph (e) will clarify the requirements

that are applicable to airplanes approved for operations at different

altitudes. Redesignated paragraph (e) is revised to remove the

masculine gender by rephrasing ``when he is seated'' to read ``when the

pilot is seated.''

Section 23.775(h), introductory text, and paragraph (h)(1) would be

added to require windshield panes of commuter category airplanes that

are directly in front of the pilots to withstand the impact of a two

pound bird. This requirement is based on a Joint Aviation Authority

recommendation to add windshield bird strike protection for commuter

category airplanes. Following receipt of the recommendations, the FAA

obtained and reviewed the International Civil Aviation Organization

(ICAO) data on bird strikes that occurred on airplanes of 19,000 pounds

or less from 1981 through 1989. These data show that approximately 550

strikes occurred and that one out of seven strikes hit the windshield.

The bird strike reports, which include information on the type of bird,

the airplane altitude and/or airspeed, show the following:

1. More than one-half of the strikes (51.8 percent) occurred

between the ground and 100 feet above the ground.

2. Another one-fourth of the strikes (26.7 percent) occurred

between 101 and 1000 feet.

3. The airplane airspeed at the time of most of the strikes (85

percent) was 150 knots or less.

4. Where bird types were reported, 27.6 percent involved small

birds and 58.6 involved medium size birds.

5. Incidents where the airplane was damaged showed that 16.9

percent resulted from small bird strikes and 64 percent resulted from

strikes involving medium size birds.

Evaluation of these data indicate that most bird strikes occur at

takeoff and landing altitudes and airspeeds, and that medium or small

birds, many weighing two pounds or less, are most often struck.

Although only a few fatalities and injuries have resulted from these

reported bird strikes, the data indicates a high probability of bird

strikes during landings and takeoffs and the potential hazards of such

strikes.

This proposed new paragraph would require that the windshield panes

directly in front of the pilots of commuter category airplanes, and the

supportive structure for these panes, must withstand the impact of a

two-pound bird at an airplane's maximum approach flap speed.

Proposed Sec. 23.775(h)(2) would require the panels of the

windshield to be arranged so that, if one is damaged, other panels will

remain that will provide visibility for continuous safe flight and

landing of the airplane.

By requiring full protection against the strike of a two-pound bird

at approach speeds, some protection will also be provided if the

airplane strikes a larger bird or strikes a bird at a higher speed.

Section 23.783 Doors

Current Sec. 23.783(b) requires that passenger doors not be located

with respect to any propeller disk so as to endanger persons using the

door. Proposed paragraph (b) would add that passenger doors must be

located in relation to any other potential hazard that could endanger

persons using the door. The propeller disk remains the prominent hazard

but other items, such as hot deicer surfaces or sharp objects on the

airplane structure, are also hazards.

Proposed new paragraph (g) would require lavatory doors, if

installed, that would not trap occupants inside a closed and locked

lavatory compartment.

Section 23.785 Seats, Berths, Litters, Safety Belts, and Shoulder

Harnesses

Seat requirements of part 23 would be clarified by moving the seat

provisions in current Sec. 23.1307(a), which require a seat or berth

for each occupant, to the introductory text of Sec. 23.785. The

requirement of Sec. 23.1413, for a metal to metal latching device for

seat belts and shoulder harnesses would also be referenced in

Sec. 23.785(b). These proposed changes would combine related seat

requirements in one section.

Section 23.787 Baggage and Cargo Compartments

Section 23.787 would be revised by extending the present

requirements for cargo compartments to baggage compartments. As

proposed, future baggage compartments on all airplane categories would

be required to: Be placarded for their maximum weight capacity; have a

means to prevent the baggage from shifting; and have a means to protect

controls, wiring, lines, and equipment or accessories that are located

in the compartment and whose damage or failure would affect safe

operation of the airplane. These standards have been applicable to

cargo compartment designs for some time and should be applied to

baggage compartments since the same safety factors are involved.

Because manufacturers recognize the need for these standards, many of

these provisions have been included in the current design of baggage

compartments and, therefore, the proposed requirements are not expected

to create a significant burden. With this revision the commuter

category requirements of Sec. 23.787(g) would be redundant and that

requirement is being removed.

Proposed revisions to this section would also move the substance of

paragraphs (d) and (f) to a proposed new Sec. 23.855, which will

address cargo and baggage compartment fire protection.

Proposed new paragraph (c) of this section would require flight

crew emergency exits on all cargo configured airplanes to meet the

requirements of Sec. 23.807. This requirement would provide increased

assurance that flight crews of all cargo airplanes will have ready

access to an emergency exit.

Section 23.791 Passenger Information Signs

This proposed new section would require at least one illuminated

sign notifying all passengers when seat belts should be fastened. This

proposed requirement applies to airplanes where flightcrew members

cannot observe occupant seats or where the flightcrew member

compartment is separated from the passenger compartment. When

illuminated, the signs must be legible to all persons seated in the

passenger compartment. Each sign must be installed so that a flightcrew

member can turn it on and off from his or her station.

Section 23.807 Emergency Exits

Proposed new Sec. 23.807(a)(4) would provide the same protection

from any propeller disk and other potential hazard for a person who

uses emergency exits as that provided by proposed Sec. 23.783(b) for a

person who uses a passenger door. (See discussion for proposed

Sec. 23.783 in this notice.)

The proposed revision of Sec. 23.807(b) would provide that the

inside handles of emergency exits that open outward must be protected

against inadvertent operation. Currently this protection is required by

applying the general safety provisions of this subchapter. The addition

of the specific requirement in Sec. 23.807(b) would clarify the need

for this protection by providing a requirement that addresses outward

opening emergency exits.

The proposed revision to Sec. 23.807(b)(5) and new

Sec. 23.807(b)(6) would apply to acrobatic and utility category

airplanes that are approved for maneuvers, such a spinning. The

proposed rule would require that emergency exits for these category

airplanes allow the occupants to abandon the airplane at certain speeds

related to such maneuvers. These emergency exits need to function under

different environmental conditions than the emergency exits on normal

category airplanes. The revision of the text in paragraph (b)(5) would

provide the same terminology that is used in added new paragraph

(b)(6).

Section 23.841 Pressurized Cabins

The proposed revision to Sec. 23.841(a) would extend the cabin

pressure requirements of current paragraph (a), which now apply to

airplanes certificated for operation above 31,000 feet, to airplanes

certificated for over 25,000 feet. Current 14 CFR part 25, JAR 25, and

proposed JAR 23 include the same requirement as this proposal. This

proposed requirement is intended to protect the airplane occupants from

harm if a malfunction occurs at altitudes where symptoms of hypoxia

occur, usually above 25,000 feet. Due to the increasing use of turbine

powered engines, more part 23 airplanes will be approved for operations

above 25,000 feet, thus exposing an increasing number or occupants, who

may have some breathing difficulties, to these altitudes. The occupants

should have the same protection provided by the airworthiness standards

of part 25 and JAR 25.

Section 23.853 Passengers and Crew Compartment Interiors

This proposal would revise the section heading from ``Compartment

Interiors'' to ``Passenger and crew compartment interiors'' for

consistency with the introductory text of the section and to clarify

the content of the section.

Section 23.855 Cargo and Baggage Compartment Fire Protection

This proposed new section would require the following:

Proposed paragraph (a) would require all sources of heat within

each cargo and baggage compartment that are capable of igniting the

compartment contents to be shielded and insulated to prevent such

ignition.

Proposed paragraph (b) would require cargo and baggage compartments

to be constructed of materials that meet the appropriate provisions of

Sec. 23.853(d)(3). Currently these requirements apply to commuter

category airplanes and to the materials used in the compartments of

these airplanes. The proposed new requirement would expand this

applicability to the cargo and baggage compartments of all part 23

airplanes. In effect, the proposed new requirement would require

materials that are self-extinguishing rather than flame resistant as

currently required under Sec. 23.787(d).

Proposed new paragraph (c) would add new fire protection

requirements for cargo and baggage compartments for commuter category

airplanes. The proposed rule would require on of the following

alternatives: (1) Either the compartment must be located where pilots

seated at their duty station would easily discover the fire or the

compartment must be equipped with a smoke or fire detector system to

warn the pilot's station. The compartment must also provide access to

the compartment with a fire extinguisher. (2) The compartment may be

inaccessible, but must be equipped with a fire detector system that

warns the pilot station, and the compartment must have ceiling and

sidewall floor panels constructed of materials that have been subjected

to and meet the vertical self-extinguishing tests of appendix F of this

part. (3) The compartment must be constructed and sealed to contain any

fire.

The proposed new section is necessary for several reasons. The

proposals for additional requirements for commuter category airplane

cargo and baggage compartments were developed after an examination of

reported incidents of inflight fires and their causes. Although most of

these incidents of inflight fires occurred on transport category

airplanes, the reported sources of the fires showed that the fires

originate from sources, such as matches in the pockets of clothing,

that are as likely to be found on part 23 airplanes as on transport

category airplanes. The same potential for inflight fires exists on

commuter category airplanes and adequate protection should be provided.

The potential for inflight fires also showed a need to examine the

flame resistant requirements of current Sec. 23.787(d) and to consider

requirements that would improve the fire protection on other categories

of airplanes. As a part of this consideration, fire protection was

discussed with certain airframe manufacturing representatives.

Information provided in these discussions showed that materials that

meet self-extinguishing flame requirements are available at about the

same cost as materials that meet flame resistance requirements. Based

on a review of the fire incidents and the information on availability

of improved materials, the proposal for Sec. 23.855(b), which would

replace current Sec. 23.787(d), would require self-extinguishing

materials to be used in the cargo and baggage compartments of all part

23 airplanes.

Section 23.867 Electrical Bonding and Protection Against Lightning and

Static Electricity

This proposed revision would change the heading that precedes the

section from ``Lightning Evaluation'' to ``Electrical Bonding and

Lightning Protection.'' It would also revise the section heading from

``Lightning protection of structures'' to ``Electrical bonding and

protection against lightning and static electricity.'' The proposed

revisions more accurately clarify the content of the section.

Section 23.1303 Flight and Navigation Instruments

The lead in for Sec. 23.1303(a) would be revised to clarify that

the instruments required by this section are the minimum ones required.

Also, Sec. 23.1303(d) would add a requirement for those airplanes whose

performance must be based on weight, altitude, and temperature to be

equipped with a free air temperature indicator. A new sentence added to

Sec. 23.1303(e)(2) would state that nuisance overspeed warnings should

not occur at lower speeds where pilots might ignore the warning. A new

paragraph (f) would propose requirements for attitude instruments that

include a means for flightcrew members to adjust the reference symbol.

Finally, it would add a new paragraph (g) to define certain specific

instruments required for a commuter category airplane.

The proposal for Sec. 23.1303(e)(2) was developed following a Joint

Aviation Authority recommendation that the warning should not occur

below the maximum operating limit speed (VMO/MMO)/ To

determine the effect that this recommended VMO/MMO limit

would have on the design of overspeed warning devices, the FAA

contacted several equipment manufacturers. These manufacturers

responded that it would be possible to establish a lower limit at

VMO/MMO, but that the design changes needed to ensure that

the warning occurred between the presently required upper limit and the

recommended lower limit would be very expensive.

The FAA notes that no known safety problem justifies that cost of

these design changes. However, the FAA is also aware that if warnings

of any type occur when the pilots know that no particular problem

exists, such warnings may become a nuisance. If warnings become a

nuisance, a pilot may disregard a warning when the airplane is

approaching a flight speed where an unsafe flight condition may occur.

Regulatory action is therefore needed to ensure that the warning will

occur within appropriate speed limits. Proposed Sec. 23.1303(e)(2)

would require manufacturers to establish a lower speed limit so that

nuisance overspeed warnings will not occur. The manufacturer would be

required to show that this limit is appropriate for the airplane design

but would not be required to set this lower limit at one specific

speed, such as VMO/MMO, which would be costly to achieve.

A new Sec. 23.1303(f) is proposed because attitude instruments are

available that provide a means accessible to the flightcrew members,

for adjusting the reference symbol through ranges that could result in

unsafe pitch angles in small airplanes. These instruments were

developed for airplanes that use high pitch angles for approved climb

or descent gradients. By permitting these airplanes to use instruments

that can be adjusted for these higher pitch angles, pilots are able to

maintain the design gradients using an instrument that provides a

normal indication at that pitch.

If such attitude instruments are installed in small airplanes,

pilots could adjust the reference symbol to ranges that could result in

unsafe pitch angles. The recommendation showed that some instruments

can be adjusted to result in pitch angles that are nearly the same as

the pitch angle that many small airplanes achieve before stalling. To

preclude potential cases of unwanted pitch adjustments of attitude

instruments installed in small airplanes, Sec. 23.1303(f) proposes to

limit the adjustment range to that limit that is needed for parallax

correction.

Proposed new Sec. 23.1303(g) would identify specific instruments,

and limits of those instruments, required for commuter category

airplanes. When the JAA initiated their consideration of commuter

category airplanes, one of the proposals they received recommended

adding the instrument requirements of Sec. 25.1303 to part 23 for

commuter category airplanes. In considering this recommendation, a

review of the requirements showed that many instruments required under

Sec. 25.1303 are presently required by the operating rules. In

addition, Sec. 23.1583(h) requires a list of the equipment that must be

installed for the kinds of operation for which the airplane is

approved. Based on the review, it was determined that many of the

requirements in Sec. 25.1303 would be redundant, and the recommendation

was not accepted.

In considering a portion of the recommendation to require a third

attitude instrument, the FAA noted that Sec. 91.531(a)(3) requires a

commuter category airplane of ten or more passengers to be operated

with a second-in-command and that Sec. 23.1321 requires flight and

navigation instruments for each required pilot. Accordingly, two

attitude instruments are required for a ten passenger, IFR approved

commuter category airplane. Service experience has shown that failures

of an attitude instrument system can occur where there will be a time

period in which the indicator appears to be working but is providing

incorrect information. During such a failure of one instrument in an

airplane equipped with only two instruments, the pilots may have

difficulty determining which instrument to follow, and hazardous flight

attitudes may result. A third attitude instrument would allow the crew

to retain reliable attitude information at all times, and thus the

proposed rule would require a third attitude instrument for commuter

airplanes operated by two pilots.

Section 23.1307 Miscellaneous Equipment

This proposal would remove the requirement of Sec. 23.1307(a) which

is being added to Sec. 23.785. The discussion of Sec. 23.785 covers

this change.

Also, the provisions of Sec. 23.1307(b)(1), (b)(2), and (b)(3), are

being removed from Sec. 23.1307. These requirements have been

previously added to Secs. 23.1361, 23.1351, and 23.1357, respectively;

therefore, they are redundant and may be removed. The designator for

paragraph (c) has also been removed from the remaining text of this

section.

Section 23.1309 Equipment, Systems, and Installations

Proposed new Sec. 23.1309(a)(4) would correct an inadvertent

omission that occurred when the FAA issued Amendment No. 23-41 (55 FR

43306, October 26, 1990). The omitted requirement was adopted by

Amendment No. 23-34 as a portion of Sec. 23.1309(d) and read: ``In

addition, for commuter category airplanes, system and installations

must be designed to safeguard against hazards to the airplane in the

event of their malfunction or failure.'' (52 FR 1833, January 15,

1987.) To correct this oversight, and to continue the single fault

provision of this paragraph, Sec. 23.1309(a)(4) is being proposed.

Section 23.1311 Electronic Display Instrument Systems

This proposal would revise Sec. 23.1311 to remove redundant

requirements and to clarify which secondary instruments are required

and the visibility requirements for these instruments. When

Sec. 23.1311 was adopted by Amendment No. 23-41 (55 FR 43306, October

26, 1990), several nonsubstantive changes were made to the proposals in

Notice No. 89-6 (54 FR 9345, March 6, 1989) to remove the redundancy

included in the notice. In the process certain provisions, such as the

one that permitted the installation of mechanical secondary

instruments, were inadvertently omitted from the final rule. Since the

final rule, discussions with airplane manufacturer representatives have

shown that the requirements defining the instrument panel location

where secondary instruments may be installed are also not clear.

Accordingly, the FAA is proposing to revise this section to correct and

clarify these portions.

Current Sec. 23.1311(a), which requires electronic display

indicator installations that are independent to each pilot station,

would be deleted because it is redundant with Sec. 23.1321(a). Section

23.1321(a) requires that each flight, navigation, and powerplant

instrument for use by any required pilot shall be located so that any

pilot seated at the controls can monitor the instruments with minimum

head and eye movement. As stated in the preamble of Notice No. 89-6 (54

FR 9345, March 6, 1989) regarding the proposed revision to

Sec. 23.1321, ``This revision also clarifies the rule relative to

instrumentation that must be provided for each pilot required for type

certification or by the applicable operating rules. If a pilot is

required by any applicable requirement, then that pilot must be

provided all instrumentation required for any operations for which the

airplane is approved.'' Accordingly, the requirements of current

Sec. 23.1311(a) would be removed.

In place of current paragraph (a), proposed Sec. 23.1311(a) would

be a revision of current paragraph (c) that would clarify what

instruments are required and the visibility of those instruments.

Proposed new Sec. 23.1311(a)(1) would require electronic display

instrument installations to meet the arrangement and visibility

requirements of Sec. 23.1321(a).

Proposed Sec. 23.1311(a) (2), (3), and (4) would be redesignated

with no changes from current Sec. 23.1311(c) (1), (2), and (3).

Proposed Sec. 23.1311(a)(5) would continue the requirement of

Sec. 23.1303(c) for a magnetic direction indicator and, in addition,

would require either an independent secondary mechanical altimeter,

airspeed indicator, and attitude indicator or individual electronic

display indicators for the altimeter, airspeed, and attitude that are

independent from the airplane's primary electrical power. These

secondary instruments may be installed in panel positions other than

the primary location as long as the selected location allows the pilot

to properly monitor the instruments and control the airplane.

The substance of proposed paragraph (a)(5) is both a substantive

change and a combination of the current Sec. 23.1311(b), which states

that certain electronic display indicators must be independent of the

airplane's electrical power system, and current Sec. 23.1311(c)(4)

which requires independent secondary attitude and rate-of-turn

instruments and specifies the location of those instruments. Proposed

Sec. 23.1311(a)(5) would delete the requirement for a rate-of-turn

instrument (in current Sec. 23.1311(c)(4)) and specify that the

required secondary instruments are those that provide altitude,

airspeed, magnetic direction, and attitude. The information that would

be provided by a secondary rate-of-turn instrument would not

appreciably add to the safe operations of the airplane if the pilot has

the information provided by the secondary attitude instrument.

Current Sec. 23.1311(b) requires that electronic display indicators

required by Sec. 23.1303 (a), (b), and (c) be independent of the

airplane's electrical power system. The original intent of the

requirement for secondary instruments, as stated in Notice No. 89-6,

was to require the installation of either mechanical instruments or

independent electronic display indicators powered by a source

independent of the airplane's electrical system. However, the current

rule does not clearly state this and does not address the installation

of mechanical instruments. Proposed Sec. 23.1311(a)(5), would allow

either secondary electronic display indicators or mechanical

instruments to provide a crew with information essential for continued

flight and landing in the event of failure in the airplane's electrical

power system.

Current Sec. 23.1311(c) (5) and (6) would be redesignated as

Sec. 23.1311(a) (6) and (7) without change.

Proposed new Sec. 23.1311 (b) and (c) would continue the

requirements of current Sec. 23.1311 (d) and (e) without change.

Section 23.1321 Arrangement and Visibility

The proposed revision to Sec. 23.1321(d) would remove the wording

that limits the instrument location requirement to airplanes

certificated for flight under instrument flight rules or airplanes

weighing more than 6,000 pounds. Instruments are for the pilot and

should be located near that pilot's vertical plane of vision without

regard to what flight rules are approved for the airplane's operation

or the maximum weight of the airplane.

Section 23.1323 Airspeed Indicating System

The proposed new Sec. 23.1323(c) would add a requirement that each

airspeed indicating system design and installation should provide

positive drainage of moisture from the system. This proposal is

consistent with the provisions required for a static system by

Sec. 23.1325(b).

If moisture enters, or accumulates in, an airspeed indicating

system, that moisture could cause erroneous airspeed indications or the

complete loss of airspeed information. The resulting loss of accurate

airspeed information would be hazardous to the operation of the

airplane; therefore, to assure the safety of the airplane, the FAA

would need to apply the more general airworthiness requirements of

Secs. 23.1301 and 23.1309 to such a system and require provisions for

drainage of moisture. Accordingly, this proposed revision of the

airspeed indicating systems requirements only clarifies the criteria

that must be applied to airspeed indicating systems.

To better organize the requirements that are applicable to the

airspeed systems on all airplane categories and those that would be

additional requirements for the airspeed systems of commuter category

airplanes, the FAA proposes to redesignate existing paragraphs (c) and

(e), respectively, as paragraphs (e) and (d). By this redesignation,

paragraphs (a), (b), (c), and (d) would apply to all airplanes, and

paragraphs (e) and (f) would include additional requirements applicable

to commuter category airplanes.

The proposal for redesignated paragraph (e) would also remove the

words ``in flight and'' from the first sentence of that paragraph. This

would remove the requirement for the airspeed indicating system to be

calibrated in flight. The requirement for an in flight calibration is

provided in paragraph (b). Proposed redesignated paragraph (e) would

apply to the calibration needed to determine the system error during

the accelerate-takeoff ground run.

As identified in the background section of this notice, the FAA is

issuing additional notices that address proposed changes to the

requirements for powerplant, flight, and airframe. Proposed revisions

to subpart G in the flight NPRM include placing all of the requirements

for what must appear in the Airplane Flight Manual (AFM) in that

subpart. With the proposals to revise the AFM requirements, the flight

NPRM also proposes that the requirement in existing Sec. 23.1323(d) (to

show the relationship between IAS and CAS in the AFM) be added to

Sec. 23.1587 as proposed new paragraph (d)(10). Because the AFM

requirement would be added to Sec. 23.1587, it no longer needs to

appear in Sec. 23.1323. Accordingly, this notice proposes to remove the

text of existing Sec. 23.1323(d).

Proposed new Sec. 23.1323(f) would provide that, on those commuter

airplanes where duplicate airspeed indicators are required, the

airspeed pitot tubes must be located far enough apart so that both

tubes will not be damaged by a single bird strike.

Section 23.1325 Static Pressure System

Current Sec. 23.1325(b)(3) establishes certain static pressure

system requirements for airplanes that encounter icy conditions.

Current Sec. 23.1325(g) exempts from the requirements of (b)(3)

airplanes that are prohibited from flight in instrument meteorological

conditions in accordance with Sec. 23.1559(b). After the adoption of

Sec. 23.1325(g), it came to the FAA's attention that there are

conditions other than instrument meteorological conditions where icing

may be encountered and, therefore, that this paragraph should also

exempt from the provisions of Sec. 23.1325(b)(3) airplanes that are

prohibited from flight in icing conditions. Accordingly,

Sec. 23.1325(g) would be revised to read, ``For airplanes prohibited

from flight in instrument meteorological or icing conditions.''

As indicated in the background section of this notice, the FAA will

issue additional notices that will address proposed changes to the

requirements for powerplant, flight, and airframe. Revisions to Subpart

G in the flight notice will propose to place all of the requirements

that specify what must appear in the AFM in that subpart. With the

proposals to revise the AFM requirements, the flight notice will also

propose that Sec. 23.1325(f) be removed and the results of the

altimeter system calibration would be required by Sec. 23.1587.

Section 23.1326 Pitot Heat Indication System

Proposed new Sec. 23.1326 would require the installation of a pitot

tube heat indicating system on those airplanes required to be equipped

with a heated pitot tube. Heated pitot tubes ensure that moisture will

not freeze in the tube and block or partially block the airspeed

indicating system. Such blockage would result in the pilots receiving

incorrect flight data with possibly disastrous results.

Due to advancements in technology, many part 23 airplane

installations now utilize equipment whose data sources are critical to

the accurate and dependable operation of that equipment. The heated

pitot tube is one such data source. The pitot heat indicating system

will advise the pilots of any inoperative heating element in the pitot

tube and that subsequent inaccuracies may result.

Part 23 airplanes certificated for flight under instrument flight

rules or for flight in icing conditions are required by current

Sec. 23.1323(e) to have a heated pitot system or an equivalent means of

preventing an airspeed indicating system malfunction due to ice

accumulation. This proposal would require such airplanes equipped with

a heated pitot tube to be equipped with a pitot tube heat indicating

system. This requirement will provide greater assurance that the pilots

will not be dangerously misled by faulty flight instrument indications

caused by pitot tube icing.

When pitot tube heat indicating system requirements were added to

part 25, the FAA noted the occurrence of at least one accident and

several incidents in which an airspeed indicating error occurred that

might have been avoided if a pitot tube heat indicating system had been

installed. Part 23 airplanes operate at lower airspeeds and over

shorter distances that do part 25 airplanes; therefore, their exposure

to moisture and temperature conditions where icing may occur is higher

than it is for transport category airplanes. Because of this

environmental exposure, the potential for an inoperative heated pitot

tube becoming a hazard to part 23 airplanes is greater.

This proposed requirement also responds to National Transportation

Safety Board (NTSB) recommendation A-92-85, which recommends requiring

a modification to certain part 23 airplanes to provide for a pitot heat

operating light similar to the light required by Sec. 25.1326 for

transport category airplanes. NTSB issued the safety recommendation,

among others, as a result of a special investigation and analysis of a

series of fatal accidents that occurred from May 31, 1989, through

March 17, 1991.

Section 23.1329 Automatic Pilot System

New Sec. 23.1329(b), adopted by Amendment No. 23-24 (58 FR 18958,

April 9, 1993), does not state clearly that stick controlled airplanes

must be equipped with the same autopilot quick release controls that

are required for airplanes with control wheels. This proposed revision

of Sec. 23.1329(b) would clarify that a quick release control must be

installed on each control stick of an airplane that can be operated

from either pilot seat.

Section 23.1337 Powerplant Instruments Installation

This proposal would revise the heading of this section to reflect

the powerplant instrument installation requirements that it contains.

The difference between this section and Sec. 23.1305 is clarified by

this change.

Section 23.1337(b) would be revised by removing the wording that

authorizes installation of only those fuel indicators marked in gallons

and pounds. In countries that use the metric system, other acceptable

units of measure for marking fuel indicators are used. This proposed

revision would allow the use of any appropriate measurement unit.

Section 23.1337(b) would also be revised by adding the word

``usable'' to the first sentence of this section. This revision is

consistent with the requirements of Sec. 23.1337(b)(1), which requires

the fuel quantity indicator to be calibrated to read ``zero'' when the

fuel in the tank is equal to the unusable fuel determined under

Sec. 23.959.

Proposed new Sec. 23.1337(b)(4) would require a ``means to

indicate'' the amount of usable fuel in each tank when the airplane is

on the ground. This requirement would ensure that a reliable means is

provided for the pilot to determine before takeoff that the amount of

fuel that is in the airplane is adequate for the intended flight. The

ability to make this preflight determination will help reduce the

number of accidents that have resulted from fuel starvation. This

proposal, which is patterned after Sec. 23.1337 (d) and (d)(1), would

not require a separate fuel indicating system. The means to determine

the amount of fuel while on the ground may be provided by a calibrated

dipstick, separate markings on the inflight fuel indicator, or any

other acceptable means selected by the manufacturer. Accordingly, this

proposal would contribute to the safe operation of the airplane and

would not appreciably add to the cost of the airplane design.

Section 23.1351 General

The proposal would revise current Sec. 23.1351 by removing portions

of paragraphs (b)(2) and (b)(3) and by removing all of paragraph

(b)(4). The removed requirements are applicable to alternators that

depend upon the battery for initial excitation or for stabilization.

This revision responds to a Joint Aviation Authority recommendation to

remove the provisions that allow a battery failure to result in the

loss of the alternator. Information in this recommendation showed that

self-excited alternators are now available for installation on newly

certificated airplanes. The FAA has verified that self-excited

alternators are now available; therefore, there is no longer a need for

the regulations to address alternators that depend upon a battery for

initial excitation and stabilization.

Revised Sec. 23.1351(c)(3) would require an automatic means for

reverse current protection. Reverse current protection is accomplished

by means that automatically detect changes in the current. The proposed

revised wording would more accurately define this function and the

equipment that would accomplish the protection.

Finally, Sec. 23.1351(f) would be revised by adding a requirement

that would require the ground power receptacle to be located where its

use will not result in a hazard to the airplane or to people on the

ground using the receptacle.

Section 23.1353 Storage Battery Design and Installation

Proposed new Sec. 23.1353(h) would require that, in the event of a

complete loss of the primary electrical power generating system,

airplane battery capacity must be sufficient to supply at least 30

minutes of electrical power to those loads essential to the continued

safe flight and landing of the airplane.

This proposal is not limited to airplanes that are approved for any

particular type of operation. Although the battery capacity needed for

an airplane approved for day visual flight rules (VFR) operations would

be much less than the capacity for an airplane approved for day/night

instrument flight rules (IFR) operations, the same level of safety

should be provided for all airplanes. While this proposal would add an

additional requirement to part 23 for normal, utility, acrobatic, and

commuter category airplanes, in practice this requirement to provide a

battery capacity sufficient to supply at least 30 minutes of electrical

power is not new to many airplane manufacturers. Certain other

countries in which part 23 airplanes have been certificated have

requirements for such a 30-minute battery capacity. Manufacturers'

experience with these requirements has shown that the only design

impact that results from complying with these requirements is the need

to install a battery with greater capacity than might otherwise be

installed. Experience has also shown that a load shedding procedure may

be necessary for certain airplanes. No other airplane design changes

would be needed.

Despite the above referenced experience record, this requirement

would be new to some manufacturers and they may have questions on how

it would be applied. For that reason, this notice discusses compliance

considerations that have emerged from experience based on substantively

equivalent requirements.

This compliance experience has shown that the rating of the battery

selected for the airplane should be sufficient to cover the loss of

capacity that would occur with battery age and the reduced capacity

that results from a realistic state of charge, which may be less than a

full charge. Using a design battery capacity that is only 75 percent of

the battery nameplate rating would be an acceptable way of accounting

for these losses.

In addition to determining the battery rating that would be needed,

the manufacturer would also need to determine the functions that would

be necessary for 30 minutes of safe flight and the landing of the

airplane. Again, experience has identified several functions. For a day

VFR approved airplane, no functions may require battery power; however,

it may be necessary to supply power for certain communication

capacities or, if the airplane has electrically powered retractable

landing gear, power may be required to lower the gear. Providing a

secondary means for lowering the gear would be an acceptable

alternative to providing electrical power or battery power for this

function.

For other types of operating approvals, providing power for the

following functions and equipment should be considered:

1. Any required flight and navigation instruments. Air driven

instruments that would function over the required period can also be

accepted for this function.

2. Cockpit and instrument lighting.

3. For IFR and icing approvals, power for the heated pitot tube.

4. For radio communication, usually one VHF communication system

with power for three to five minutes of transmission would be

acceptable.

5. Functions needed for safe night flight and night landing of the

airplane.

6. Electronic engine ignition systems.

7. Any functions that cannot be readily shed following the loss of

generator power.

8. Engine inlet heat or deicing protection required for normal

operation of the airplane.

Although power for the listed functions may provide for the safe

operation and landing of most airplanes, individual airplane designs

may require the consideration of additional functions.

In applying these rules it may be assumed that airframe and engine

icing protection equipment would not be operating at the time of the

generator system failure. Power for icing protection would not be

required if the icing protection equipment is not required for the

normal operation of the airplane.

This proposal would require additional battery capacity and would

not alter or supersede any other requirements in this part for separate

or dedicated emergency power supplies. When requirements such as those

in current Sec. 23.1331(a) or in proposed Sec. 23.1311(a)(5) are

applicable to the airplane design, these power supplies are required to

provide a needed level of safety for that function; therefore, that

power source must be supplied.

Section 23.1359 Electrical System Fire Protection

Proposed new Sec. 23.1359 would require smoke and fire protection

for electrical system installations. The provisions of Sec. 23.1359(a)

of this proposal state that electrical systems must meet the applicable

requirements of Secs. 23.863 and 23.1182.

Proposed Sec. 23.1359(b) would require that the electrical systems

components installed in designated fire zones and used during emergency

procedures be fire resistant. This provision is needed to clarify the

requirements for electrical system components that may be installed in

the designated fire zones identified in Sec. 23.1181.

Finally, Sec. 23.1359(c) provides burn criteria for electrical wire

and cables. A proposed revision to appendix F of part 23 that would add

appropriate wire testing criteria is included in this notice.

This proposed burn criteria for wire is necessary because of the

increased use of electrical systems in the design of part 23 airplanes

and the resulting increase in the amount of electrical wire being

installed. This increased use results in the need to ensure that wire

insulating material does not become the source of an in-flight fire

and/or that it does not propagate a fire from another source. The

electrical wire burn requirements in this proposal, along with the

testing identified in revised appendix F, would ensure that installed

electrical wire has insulating material that reduces the possibility of

hazardous in-flight fires.

Section 23.1361 Master Switch Arrangement

To harmonize with the JAR this proposal would revise

Sec. 23.1361(c) by making an editorial change to remove the last two

words of the paragraph that read ``in flight.''

Section 23.1365 Electrical Cables and Equipment

This proposal would revise Sec. 23.1365(b) and would add three new

paragraphs.

Section 23.1365(b) would be revised in relation to proposed new

Sec. 23.1359(c), which would require self-extinguishing insulated

electrical wires and cables. Current Sec. 23.1365(b) requires that

cable and associated equipment that would overheat in the event of

circuit overload or fault must be flame resistant and may not emit

dangerous quantities of toxic fumes. The proposed revisions to

Sec. 23.1365(b) would remove the reference to electrical cables from

the flame resistance requirement since the cables would be required to

have self-extinguishing insulation under Sec. 23.1359(c). The

requirement for electrical cables and the associated equipment that

would overheat to not emit dangerous quantities of toxic fumes has been

retained.

The text of Sec. 23.1365(b) that includes the words ``at least

flame resistant '' would also be revised by removing the words ``at

least''. The removed words implied that there were burn requirements,

other than the ones in this section, that must be met.

The three paragraphs that would be added by this proposal would

require: (1) The identification of electrical cables, terminals, and

connectors; (2) the protection of electrical cables from damage by

external sources; and (3) installation criteria for cables that cannot

be protected by a circuit protection device.

As identified in the discussion of proposed Sec. 23.1359, there is

an increasing use of electrical systems in part 23 airplanes. The

resulting increase in the number of electrical wires used in part 23

airplanes makes proper installation difficult. The proposal for

electrical cable identification would provide better assurance that the

cables will be correctly installed initially and correctly reinstalled

when airplane maintenance or modifications are accomplished. The other

proposed new requirements would provide installation criteria that will

ensure the protection of cables under circumstances that can be

expected from the increased use of electrical systems.

Section 23.1383 Taxi and Landing Lights

The landing light requirements of Sec. 23.1383 would be revised by

adding taxi lights to this section. When the landing light requirements

were included in the normal, utility, acrobatic, and commuter category

requirements, the same lights were used for both night landing and

taxiing of the airplane. Due to availability of different types of

lights, separate lights are now frequently installed for landing and

for taxiing. Including the word ``taxi'' in the heading would clarify

that the requirements cover both kinds of lights.

Current Sec. 23.1383(a), which requires the lights to be

acceptable, would be deleted because it is unnecessary to state this.

All lights that are found to meet the requirements of this section and

other directly related airworthiness requirements are acceptable. The

paragraphs would be redesignated accordingly.

Current Sec. 23.1383(b)(3) requires that a landing light must be

installed to provide enough light for a night landing. Proposed

Sec. 23.1383(c) would revise ``night landing'' to ``night operation''

since the requirements would also cover taxiing and parking. Proposed

new paragraph (d) would require the lights to be installed so that they

do not cause a fire hazard. This clarifies the need for such an

evaluation.

Section 23.1401 Anticollision Light System

This proposal would revise Sec. 23.1401 to require the installation

of an anticollision light system on all part 23 airplanes. Current

Sec. 23.1401 requires an anticollision light system only if

certification for night operations is requested. When the requirements

for anticollision lights were first added to the Civil Air Regulations

(CAR), part 3, in 1957, those requirements were needed to increase the

conspicuity of the airplanes during night operations because of the

increasing air traffic density and the newer airplanes' capability to

attain higher speeds. At the time, the operating conditions did not

show a need for such lights for daylight operations.

The number of airplanes that have been added to the fleet and the

increasing speeds resulting from improved technology, especially the

increasing use of turbine engines, now necessitates the conspicuity

provided by anticollision lights for day operations as well. The FAA

Accident and Incident data for the period 1984 through 1990 shows that

269 aircraft were involved in midair collisions in which 108 fatalities

occurred. A review of this data shows that 234 of these aircraft were

involved in accidents or incidents that occurred during VFR conditions

and that 224 were involved in accidents or incidents during day

operations. The other 10 were involved in operations at night or dusk.

The reports on 35 aircraft did not identify the type of condition that

existed.

Of the types of aircraft identified by the reports in this data, 60

were balloons, gliders, or other aircraft that were not certificated

under part 23 and whose level of safety would not be changed by this

proposal. When the data is revised by removing those reports, it shows

that 209 small, part 23 airplanes operated under VFR conditions were

involved in midair accidents or incidents and that at least 167 of

these airplanes were being operated in day VFR conditions. Because the

occupant capacity of all the aircraft in the data ranged from one to

ten, it can be assumed that the fatality rate of .401 per aircraft (108

fatalities/269 aircraft) would be nearly the same for the 167 small

airplanes operating in day VFR conditions as it was for the 269

aircraft. Based on this assumption, there would have been approximately

67 fatalities that occurred in these 167 small airplane accidents and

incidents.

The reports do not show if the airplanes involved were equipped

with or were using anticollision lights. They do show that a need

exists to reduce the number of accidents. Requiring the installation of

anticollision lights on all newly certificated airplanes and, as

proposed by revised Sec. 91.209 in this notice, requiring operation of

anticollision lights during day operations would increase the

airplane's conspicuity and contribute to a reduction in the number of

accidents. Even if such action is only 25 percent effective, a review

of the 6-year service history indicates that approximately 17

fatalities could be avoided in a similar 6-year period. Many

manufacturers have realized the additional safety that can be provided

by the increased airplane conspicuity of using anticollision lights and

have elected to install an anticollision light system on all of the

airplanes they produce. Therefore, most airplanes are now being

manufactured with an installed anticollision light system, and the FAA

expects that this proposal would not result in an economic burden on

the aviation community.

Section 23.1431 Electronic Equipment

This proposal would add three new paragraphs to Sec. 23.1431.

Proposed new paragraph (c) would require that airplanes required to be

operated by more than one flightcrew member must be evaluated to

determine if the flightcrew members can converse without difficulty

when they are seated at their duty stations. Accident investigations

have shown that, in some instances, conversation between the flightcrew

members was severely hindered by the noise level in the cockpit and

that the inability to communicate contributed to the accident. If the

required evaluation shows that the noise level does not impair

conversation, no further action is required. However, if the evaluation

shows that conversation will be difficult, an intercommunication system

would be required.

Proposed new paragraph (d) would require that if installed

communication equipment includes any means of switching from receive to

transmit, the equipment must use ``off-on'' transmitter switching that

will ensure that the transmitter is turned off when it is not being

used. Transmitting equipment that remains in the transmit mode when not

being used blocks the frequency being used and can create an unsafe

condition by preventing other needed communication.

Proposed new paragraph (e) would require that if provisions for the

use of communications headsets are provided, it must be demonstrated

that flightcrew members can hear aural warnings when a headset is being

used. Aural warnings are required to warn the pilot of a condition that

necessitates the pilot's taking action; therefore, it is necessary to

ensure that such warnings would be effective even when headsets are

being used.

During the development of the proposed new requirements in

paragraphs (c) and (e), the FAA considered proposing a requirement that

compliance demonstrations should be conducted under actual cockpit

noise conditions when the airplane is being operated. The FAA, however,

ultimately determined that such a requirement could result in

demonstrations conducted under more severe noise conditions than

needed. Accordingly, no such requirement is being proposed. If the FAA

determines in the future that noise conditions for demonstrations need

to be specified, the FAA will define these conditions in advisory

material.

Section 23.1435 Hydraulic Systems

Since the close of the comment period for the Small Airplane

Airworthiness Review Program Notice No. 3 (55 FR 40598, October 3,

1990), now adopted by Amendment No. 23-43 (58 FR 18958, April 9, 1993),

the FAA has been involved in discussions of the installation of

hydraulic accumulators that are permitted by Sec. 23.1435(c). These

discussions have shown that applicants are likely to find

Sec. 23.1435(c) difficult to understand because of the way it is

worded. This notice would further revise Sec. 23.1435(c) to clarify

under what circumstances a hydraulic accumulator and reservoir may be

installed on the engine side of any firewall.

Section 23.1447 Equipment Standards for Oxygen Dispensing Units

Proposed new Sec. 23.1447(a)(4) would require that if radio

equipment is installed in an airplane, flightcrew oxygen dispensing

units must be designed to allow the use of communication equipment when

oxygen is being used. If radio equipment is installed, that equipment

cannot perform its intended function if the flightcrew is not provided

the proper means for its utilization under all operating conditions,

including operations when oxygen is being used.

This proposal would not require all flightcrew oxygen dispensing

units to be equipped with communication equipment. Since an airplane

may be operated in uncontrolled airspace, where two-way radio

communication is not required and, at the same time, be at altitudes

where oxygen is required for the flightcrew members, some airplanes

have a crew oxygen system but no radio equipment. It would be

inappropriate to require the flightcrew dispensing units of those

airplanes to be equipped with communication equipment.

The proposed revisions to Sec. 23.1447(d) would require the

flightcrew oxygen dispensing units to be automatically presented before

the cabin pressure altitude exceeds 15,000 feet or be the quick-donning

type if the airplane is certificated for operation above 25,000 feet.

The requirement in paragraph (e) for the passenger dispensing units to

be automatically presented if the airplane is approved for operation

above 30,000 feet has not been revised. The revision to paragraph (d)

would provide the flightcrew and the airplane passengers the same level

of safety as provided by other airworthiness standards. This proposed

revision is also consistent with the proposed revision of Sec. 23.841

in this notice.

Section 23.1451 Fire Protection for Oxygen Equipment

This proposed new section would specify that fire protection is

needed for oxygen equipment installations. Section 23.1451 (a) and (b)

would, respectively, prohibit the installation of oxygen equipment in

designated fire zones and require that oxygen system components be

protected from the heat from designated fire zones.

Proposed Sec. 23.1451(c) would require oxygen equipment and lines

to be separated from other equipment or to be protected in a manner

that would prevent escaping oxygen from striking grease, fluids, or

vapors. The impingement of pure oxygen on certain materials will lower

their combustion point to a value where ignition will occur in ambient

conditions thereby creating a potential source for an airplane fire. In

one instance, an airplane was destroyed by fire that resulted when

escaping oxygen impinged on lubricating material during maintenance of

the airplane. The proposed new section would ensure that oxygen systems

are protected to prevent fire hazards that can result from escaping

oxygen.

Section 23.1453 Protection of Oxygen Equipment From Rupture

This proposed new section would clarify the rupture protection

needed for oxygen system installation. Rupture protection for oxygen

systems is currently required by the application of the structures load

requirements of part 23. The addition of Sec. 23.1453(a) would clarify

the application of these load requirements and would identify the need

to consider maximum temperatures and pressures that may be present.

Section 23.1453(b) would identify the protection to be provided for

high pressure oxygen sources and the high pressure lines that connect

such sources to the oxygen system shutoff valves.

Section 23.1461 Equipment Containing High Energy Rotors

This proposal would revise paragraph (a) of this section to clarify

that the requirements apply to high energy rotors included in an

auxiliary power unit (APU). Following the addition of this section to

part 23, the FAA issued a policy message that showed Sec. 23.1461 was

adopted to cover equipment such as APU's and constant speed drives that

may be installed on small airplanes. The proposed revision of paragraph

(a) will clarify the applicability of this section as identified in

that policy material.

Appendix F

This proposal would revise appendix F to provide the procedures

needed to test electrical wire to ensure that the wire meets the burn

requirements of Sec. 23.1359. It would also add procedures for meeting

the 45 degree and 60 degree angle burn test requirement proposed for

Secs. 23.855(c)(2) and 23.1359(c), respectively. Paragraph (b) would be

revised to clarify the specimen configuration that must be used in the

testing procedures that are proposed to be added by this notice.

Section 91.205 Powered Civil Aircraft With Standard Category U.S.

Airworthiness Certificates: Instrument and Equipment Requirements

Proposed new Sec. 91.205(b)(11) would require that airplanes

certificated under Sec. 23.1401 of this notice be equipped with an

anticollision light system for day VFR operations. Day VFR operations

are discussed under Sec. 23.1401 of this notice.

Section 91.209 Aircraft Lights

Proposed new Sec. 91.209(b) would require that airplanes equipped

with an anticollision light system be operated with the anticollision

light system lighted during all types of operations, except when the

pilot determines that, because of operating conditions, it would be in

the interest of safety to turn the lights off.

Regulatory Evaluation, Regulatory Flexibility Determination, and Trade

Impact Assessment

Proposed changes to Federal regulations must undergo several

economic analyses. First, Executive Order 12866 directs that each

Federal agency shall propose or adopt a regulation only upon a reasoned

determination that the benefits of the intended regulation justify its

costs. Second, the Regulatory Flexibility Act of 1980 requires agencies

to analyze the economic effect of regulatory changes on small entities.

Third, the Office of Management and Budget directs agencies to assess

the effects of regulatory changes on international trade. In conducting

these analyses, the FAA has determined that this rule: (1) Would

generate benefits that would justify its costs and is not a

``significant regulatory action'' as defined in the Executive Order;

(2) is not ``significant'' as defined in DOT's Policies and Procedures;

(3) would not have a significant impact on a substantial number of

small entities; and (4) would not constitute a barrier to international

trade. These analyses, available in the docket, are summarized below.

Regulatory Evaluation Summary

This section summarizes the costs and benefits of each provision of

the proposed rule. Many of the provisions would impose either no cost

or a negligible cost. Such provisions are typically administrative,

editorial, clarifying, relieving, or conforming in nature. In addition,

the FAA holds that certain provisions have a potential safety benefit

that can be achieved with no incremental cost, due primarily to the

fact that this rule would apply to future certificated airplanes and

retrofitting would not be required. All provisions of the proposed

rule, including those with no or negligible costs, are summarized

below. Only those provisions with non-negligible costs are further

evaluated in the section that follows. The reader is directed to the

full regulatory evaluation for additional information.

----------------------------------------------------------------------------------------------------------------

Section Incremental cost Benefit

----------------------------------------------------------------------------------------------------------------

Section 23.677Trim systems........... Negligible.......................... Safety.

Section 23.691 Artificial stall None................................ Administrative.

barrier system.

Section 23.697Wing flap controls..... $480 per certification and $100 per Nominal safety and relief.

airplane for affected airplanes.

Section 23.701Flap interconnection... None................................ Clarification.

Section 23.703Takeoff warning system. $240 per certification for Nominal safety and relief.

evaluation. Where necessary, $5,120

per certification, $1,000 per

airplane and $100 per year.

Section 23.723Shock absorption tests. None................................ Editorial.

Section 23.729Landing gear extension (e). None.......................... Clarification.

and retraction system.

(g). Negligible, general practice.. Minor; general practice.

Section 23.735Brakes................. (a). None.......................... Editorial clarification.

(c). None.......................... Administrative.

(e). $240 per certification........ Minor safety.

Section 23.745Nose/Tail wheel None................................ Minor. Avoids special conditions.

steering.

Section 23.775Windshields and windows (a). None.......................... Relieving.

(c). None.......................... Clarification.

(h). Up to $350,000 per Safety.

certification.

Section 23.783Doors.................. (b). None.......................... Minor safety.

(f). $25 per airplane.............. Safety.

Section 23.785Seats, births, litters, None................................ Editorial organization.

safety belts and shoulder harnesses.

Section 23.787Baggage and cargo (a). $1 per airplane............... Minor safety.

compartments.

(b). $60 per certification and up Safety.

to $100 per airplane.

(c). None.......................... Clarification.

Section 23.791Passenger information $60 per certification, up to $200 Safety.

signs. per airplane, and a negligible

effect on operating costs.

Section 23.807Emergency exits........ (a)(4). Expected negligible........ Minor safety.

(b) and (b)(5). None............... Clarification and editorial.

(b)(6). Where chosen, $10,000 per Safety.

certification and $500 per airplane.

Section 23.841Pressurized cabins..... $1,000 per certification and $2,000 Safety.

per airplane.

Section 23.853Passenger and crew None................................ Editorial.

compartment interiors.

Section 23.855Cargo and baggage (a). Less than $40 per airplane.... Minor safety.

compartment fire protection.

(b). Less than $200 per airplane... Safety.

(c). Potentially as high as $1,800 Safety.

per certification, $4,550 per

airplane, and $100 per year.

Section 23.867Electrical bonding and None................................ Editorial.

protection against lightning and

static electricity.

Section 23.1303Flight and navigation Introduction. None.................. Clarification.

instruments.

(d). $500 per certification and Safety.

$350 per airplane.

(e)(2). None....................... Minor safety.

(f). None.......................... Minor safety.

(g)(1). Up to $2,000 per airplane.. Safety.

(g)(2). None....................... Minor safety.

(g)(3). Up to $3,600 per Safety.

certification and $7,000 per

airplane.

Section 23.1307Miscellaneous None................................ Editorial and conforming.

equipment.

Section 23.1309Equipment, systems, None................................ Minor safety.

and installations.

Section 23.1311Electronic display None................................ Clarifying, editorial, and

instrument systems. relieving.

Section 23.1321Arrangement and None................................ Minor safety.

visibility.

Section 23.1323Airspeed indicating None................................ Minor safety.

system.

Section 23.1325Static pressure system None................................ Relieving.

Section 23.1326Pitot heat indication $2,800 per certification, $1,600 per Safety.

system. airplane.

Section 23.1329Automatic pilot system None................................ Clarifying.

Section 23.1337Powerplant instruments Heading and (b). None.............. Clarifying, relieving.

installation.

(b)(4). Negligible................. Safety.

Section 23.1351General............... (b). None.......................... Administrative.

(c)(3). None....................... Clarifying.

(f). None.......................... Minor safety.

Section 23.1353Storage battery design Where necessary, up to $30 per five Safety.

and installation. years capital, up to $10 per year

operating, and $600 per

certification.

Section 23.1359Electrical system fire (a). None.......................... Clarifying emphasis.

protection.

(b). Negligible.................... Clarifying.

(c). $240 per certification........ Safety.

Section 23.1361Master switch None................................ Editorial.

arrangement.

Section 23.1365Electrical cables and (b). None.......................... Conforming editorial.

equipment.

(d). $4,400 per certification and Safety.

$100 per airplane.

(e). None.......................... Minor safety.

(f). Negligible.................... Minor safety.

Section 23.1383Taxi and landing None................................ Editorial update.

lights.

Section 23.1401Anticollision light Where necessary, $2,400 per Safety.

system. certification and $1,600 per

airplane.

Section 23.1431Electronic equipment.. (c). Where necessary, up to $1,200 Safety.

per certification and $1,600 per

airplane.

(d). Negligible. Included above.... Minor safety.

(e). None or negligible............ Safety.

Section 23.1435Hydraulic systems..... None................................ Clarifying.

Section 23.1447Equipment standards (a)(4). Up to $2,000 per airplane.. Safety.

for oxygen dispensing units.

's (d) and (e). None............... Minor safety.

Section 23.1451Fire protection for None................................ Safety.

oxygen equipment.

Section 23.1453Protection of oxygen $960 per certification.............. Safety.

equipment from rupture.

Section 23.1461Equipment containing None................................ Clarifying.

high energy rotors.

Appendix F to part 23--Test procedure None. Considered above.............. Minor safety.

Section 91.205Powered civil aircraft None................................ Safety, considered above.

with standard category U.S.

airworthiness certificates:

Instrument and equipment

requirements.

Section 91.209Aircraft lights........ $25 per year per airplane........... Safety, considered above.

----------------------------------------------------------------------------------------------------------------

Evaluation of Provisions With Non-Negligible Projected Costs

This section describes and evaluates those provisions of the

proposed rule that are expected to impose costs that are not

negligible.

Section 23.697 Wing Flap Controls

Proposed new Sec. 23.697(c) would provide safety standards for the

wing flap control lever designs installed in airplanes that use wing

flap settings other than fully retracted when showing compliance with

Sec. 23.145. The FAA estimates that an aerospace engineer could design

the flap control lever to meet the proposed requirement in 8 hours at a

burdened rate of $60 per hour, totalling $480 per certification. The

control lever itself would impose an incremental cost, including

installation, of approximately $100 per airplane.

The nominal benefits of this provision would derive from the

increased safety afforded the pilot in positively selecting the proper

flap setting to maintain longitudinal control. In fact, if a flap

position other than fully retracted were needed to maintain

longitudinal control: (1) That position would be necessary to prevent

an unsafe condition, (2) the airplane would not be certificated under

that design, and (3) the airplane would have to be redesigned so that

intermediate flap positions would not be needed for control. Proposed

paragraph (c) would allow the identification of an intermediate flap

position and the positive means of selecting that position. This

alternative would rectify the unsafe condition without requiring the

manufacturer to redesign the airplane.

Section 23.703 Takeoff Warning System

This proposed new section would require a takeoff warning system on

some commuter category airplanes. The requirement would be applicable

if the flight evaluation shows that an unsafe takeoff condition would

result if lift devices or longitudinal trim devices are set to any

position outside the approved takeoff range. If the evaluation shows

that no unsafe condition would result at any setting of these devices,

a takeoff warning system would not be required. For those airplanes on

which a warning system must be installed, the proposed rule would

provide requirements for the installation of the system.

The FAA estimates that an evaluation to determine whether a takeoff

warning system would be needed would cost $240 (4 hours of engineering

at a burdened rate of $60 per hour). Where needed, the integration

design of a warning system would cost $2,400 (40 hours at $60 per

hour). In addition, an incremental 4 hours of flight testing at a cost

of $2,720 ($500 per hour for two test pilots and $180 per hour for

fuel) would be needed to demonstrate the system's performance. The FAA

estimates that the system, including acquisition, wiring, micro

switches, and labor, would add approximately $1,000 to the cost of each

airplane required to have one. Maintenance of such a system would cost

approximately $100 per year. The FAA solicits comments from interested

parties concerning the expected certifications that would require a

takeoff warning system and the concomitant costs to acquire, install,

and maintain them.

The nominal benefits of this proposal would derive from the

increased safety provided by the takeoff warning system that would

activate whenever lift or longitudinal trim devices are not set within

their approved takeoff ranges. In fact, if an evaluation showed that

positions of the lift or longitudinal trim devices could create an

unsafe condition on takeoff, the manufacturer would be required, under

existing regulations, to redesign the devices so that the unsafe

positions could not be obtained. The proposed section would provide

relief by allowing the applicant to install a warning system rather

than redesigning the trim device(s).

Section 23.735 Brakes

Proposed new Sec. 23.735(e), applicable to commuter category

airplanes, would require establishing the minimum rejected takeoff

brake kinetic energy capacity rating of each main wheel brake assembly.

Section 23.45 provides that the determination of the accelerate-stop

distance for commuter category airplanes be made in accordance with the

applicant's procedures for operation in service. This proposed

requirement is needed to ensure that the brakes will perform safely

under accelerate-stop conditions.

Under the proposed rule, manufacturers of commuter airplanes could

determine the kinetic energy absorption requirements either through a

conservative rational analysis of the sequence of events expected

during a rejected takeoff or by using a formula presented in proposed

new Sec. 23.735(e)(2). It is projected that the necessary determination

would cost $240 based on four hours of engineering at a burdened rate

of $60 per hour. The potential benefits of the proposal would derive

from the added safety that would be provided by establishing beforehand

the minimum necessary kinetic energy capacity rating of each main wheel

brake assembly under rejected-takeoff conditions.

Section 23.775 Windshields and Windows

Introductory text and paragraph (h)(1) would be added to require

that commuter category windshield panes that are directly in front of

the pilots be able to withstand the impact of a two pound bird at

maximum approach flap speed. By requiring full protection against the

strike of a two-pound bird at approach speed, additional protection

would also be provided if the airplane strikes a larger bird or strikes

a bird at a higher speed.

Proposed Sec. 23.775(h)(2) would further require the panels of the

windshield to be so arranged that, if one is damaged, other panels

would remain to provide visibility for continuous safe flight and

landing.

The potential costs of proposed Sec. 23.775(h) would vary depending

on the circumstances of the affected manufacturer. Industry sources

estimate that the total nonrecurring cost per model would range from

$250,000 to $350,000, consisting of: (1) Up to $200,000 for a bird

strike test article (``bird gun'') if the manufacturer does not have

one; and (2) up to $150,000 of time and materials costs for the actual

testing.

A manufacturer that has a bird strike test article would not incur

additional capital test costs. Most manufacturers would incur up to

$150,000 in time and materials costs for the actual testing, but even

these costs would be mitigated by the existing need of most

manufacturers to perform such tests for export sales to JAA member

countries.

Industry sources estimate that there would be no identifiable

increment in design or tooling costs since the windshield would be an

integral part of the initial design. Similarly, little or no recurring

costs per airplane (incremental materials, installation, or weight) are

projected since it is reasonable to assume that the pressure load, as

compared to bird strike resistance, would be the controlling factor in

the windshield design strength.

The benefit of the proposed rule is the incremental protection

against bird strikes that would be afforded to commuter category

airplanes. The FAA has reviewed International Civil Aviation

Organization (ICAO) data on bird strikes that occurred on member-

country airplanes of 19,000 pounds or less than 1981 through 1989.

These data show that approximately 550 strikes occurred and that one

out of seven strikes hit the windshield. The data show that:

1. Almost 52 percent of the strikes occurred at altitudes of less

than 100 feet, and 26.7 percent occurred between 101 and 1000 feet.

2. Eighty-five percent of the strikes occurred at airspeeds of 150

knots or less.

3. Where bird types were reported, 27.6 percent of the strikes

involved small birds and 58.6 involved medium size birds (2 pounds or

less).

4. Incidents where the airplane was damaged showed that 16.9

percent resulted from small bird strikes and 64 percent resulted from

medium size bird strikes.

These data show that most bird strikes occur at takeoff and landing

altitudes and airspeeds, and that birds weighing two pounds or less are

struck most often. The standards of the proposed provision are based on

these statistics. Few fatalities and injuries resulted from the bird

strikes reported in the ICAO data. Similarly, a review of NTSB accident

records between 1982 and 1992 revealed no U.S. accidents resulting from

bird strikes to the windshields of commuter category airplanes. As a

result, the FAA is not able to illustrate the justification of this

provision on the basis of historical accidents. Instead, the standards

are being proposed based on the expert recommendations of the ARAC. It

is also noted that this standard will be applied in JAA member

countries and that U.S. manufacturers wishing to export to those

countries would be required to meet the standard in any event.

Given that this provision cannot be quantitatively supported on the

basis of past accidents alone, the FAA expressly requests public input

and comments on its expected costs and potential benefits.

Section 23.783 Doors

Proposed new paragraph (f) would require that the locks on lavatory

doors, if installed, be designed so that they would not trap occupants.

Lavatory door locks used in transport category airplanes (see

Sec. 25.783) meet the requirements of this proposed rule. The FAA

estimates that the incremental cost of this provision would be no more

than $25 per lock. The proposal would reduce the likelihood that

occupants would be trapped in a locked lavatory, both in emergency and

non-emergency situations.

Section 23.787 Baggage and Cargo Compartments

The proposed rule would extend to normal, utility, and acrobatic

airplanes the existing commuter requirement to prevent baggage from

hazardous shifting. The FAA estimates that an aerospace engineer would

be required for 1 hour, at a burdened cost of $60 per hour, to analyze

the subject loads that would need to be constrained. Tiedowns would

cost approximately $50 per baggage compartment, or no more than $100

per airplane. These additional costs would apply only to normal,

utility, or acrobatic airplanes since commuter category airplanes are

already subject to the requirement under the existing rule.

The potential benefits of the proposed provision include the

reduced likelihood: (1) That baggage compartments would be overloaded,

(2) that stowed baggage would shift dangerously, and (3) that essential

co-located equipment or wiring would be damaged.

Section 23.791 Passenger Information Signs

This proposed new section would require at least one illuminated

sign notifying all passengers when seat belts should be fastened. The

requirement would apply only to airplanes where flightcrew members

could not observe occupant seats or where the flightcrew compartment is

separated from the passenger compartment. The signs would have to be

legible to all seated passengers and be operable from a crewmember

station.

The FAA estimates that an aerospace engineer could design the

required sign(s) in 1 hour, at a burdened rate of $60 per hour. The

sign would cost approximately $200 per airplane, including parts and

installation costs. Maintenance costs for bulb replacement would be

negligible. The weight penalty associated with the light system would

also be minor (no more than 2 pounds).

The safety benefits of the proposed change would derive from the

increased likelihood that passengers would know when their seat belts

should be fastened.

Section 23.807 Emergency Exits

Proposed new Sec. 23.807(a)(4) would provide the same hazard

protection for a person using an emergency exit as that provided by

proposed Sec. 23.783(b) for a person who uses a passenger door.

Emergency exits could not be located with respect to a propeller disk

or any other hazard in a manner that would endanger persons using that

exit.

The FAA holds that no incremental cost would be incurred to meet

the standards of the proposed provision for newly certificated

airplanes. However, this notice specifically requests that interested

parties submit comments on the potential costs and methods of

compliance that manufacturers would choose to comply with this proposed

requirement.

The proposed revision to Sec. 23.807(b)(5) would editorially revise

the current egress requirements for acrobatic airplanes. New

Sec. 23.807(b)(6) would establish similar egress standards for utility

category airplanes that are certificated for spinning. Industry sources

estimate that an aerobatic, quick-release door would cost an

incremental $10,000 in engineering design per affected airplane model

and an additional $500 per production airplane. Little or no additional

weight is expected. These costs would apply only in cases where the

manufacturer determines that the marketplace return of a combination

type certificate would outweigh the additional costs of design and

production.

Section 23.841 Pressurized Cabins

The proposed revision to Sec. 23.841(a) would extend the cabin

pressure requirements of current paragraph (a), which now apply to

airplanes certificated for operation above 31,000 feet, to airplanes

certificated for operation above 25,000 feet. Current part 25, JAR 25,

and proposed JAR 23 include the same requirement proposed here. This

proposed requirement is intended to protect airplane occupants from

harm if a malfunction occurs at altitudes where symptoms of hypoxia

occur, usually above 25,000 feet.

For airplanes that will be certificated for maximum altitude

operation between 25,000 feet and 31,000 feet, the proposal would

necessitate two additional pressure altitude regulators and associated

plumbing. Industry sources estimate that the proposed requirement would

cost an incremental $1,000 in engineering design per affected airplane

model and $2,000 per production airplane. Any additional weight would

be negligible.

The benefits of the proposal would derive from the incremental

protection against hypoxia afforded to occupants of airplanes

certificated for maximum altitude between 25,000 and 31,000 feet. Due

to the increasing use of turbine engines, more part 23 airplanes are

likely to be approved for operation above 25,000 feet. In the absence

of this proposed rule, an increasing number of occupants would be

exposed to the potential for harm in the event of a failure or

malfunction of the pressure system on these airplanes.

Section 23.855 Cargo and Baggage Compartment Fire Protection

Proposed paragraph (a) would require all sources of heat within

each cargo and baggage compartment that are capable of igniting the

compartment contents to be shielded and insulated to prevent such

ignition. Existing Sec. 23.787(f) requires that cargo compartment lamps

be installed so as to prevent contact between the lamp bulb and cargo.

The proposal would clarify and extend this provision to include all

sources of heat for baggage as well as cargo compartments.

Lights and (rarely) heaters for pets are typically the only sources

of heat located in a baggage or cargo compartment. A wire cage, costing

no more than $20, around the heat source would meet these requirements.

The FAA estimates that the cost of compliance per airplane would be no

more than $40 in those rare cases where such protection would not have

been provided anyway. The benefit of the proposed provision is a

reduction in the possibility of fire caused by the ignition of

compartment contents by lights or heaters.

Proposed paragraph (b) would require cargo and baggage compartments

to be constructed of materials that meet the appropriate provisions of

Sec. 23.853(d)(3). Currently these requirements apply to commuter

category airplanes and to the materials used in the compartments of

these airplanes. The proposed new requirement would expand this

applicability to the cargo and baggage compartments of all part 23

airplanes. In effect, the proposed new requirement would require

materials that are self-extinguishing rather than flame resistant as

currently required under Sec. 23.787(d).

Information provided by manufacturers shows that materials that

meet self-extinguishing flame requirements are available at a slightly

higher cost than materials that meet flame resistant requirements. The

FAA conservatively estimates that the incremental costs of complying

with proposed Sec. 23.855(b) would be less than $200 per airplane. The

safety benefits of this provision would be an increase in cargo and

baggage compartment fire protection.

Proposed new paragraph (c) would add new fire protection

requirements for cargo and baggage compartments for commuter category

airplanes. The proposed rule would require one of the following three

alternatives:

(1) The compartment just be located where pilots seated at their

duty station would easily discover the fire or the compartment must be

equipped with a smoke or fire detector system to warn the pilot's

station. The compartment must also be accessible for fire extinguisher

application.

(2) The compartment may be inaccessible, but must be equipped with

a fire detector system that warns the pilot station, and the

compartment must have ceiling and sidewall floor panels constructed of

materials that have been subjected to and meet the vertical self-

extinguishing tests of appendix F to part 23.

(3) The compartment must be constructed and sealed to contain any

fire.

The FAA cannot predict the designs of cargo and baggage compartment

for future airplanes. If manufacturers choose to use smoke detectors,

however, no more than 2 smoke detectors would be required per airplane.

An aerospace engineer could determine the most appropriate location and

design the smoke detector system in approximately 30 hours at a

burdened rate of $60 per hour, for a total cost of $1,800 per

certification. Two detectors, including wiring and installation, are

estimated to cost about $4,550. Maintenance costs for the smoke

detectors would cost approximately $100 per year. Materials that would

meet the vertical self-extinguishing tests of appendix F (see option 2

in the discussion above) would result in incremental costs of less than

$200 per airplane.

The FAA estimates that it would cost $500 to construct a sealed

compartment, or a total of $1,000 for 2 compartments, if the

manufacturer chooses that method of complying with the proposed

requirement (see option 3 in the discussion above).

Irrespective of the individual compliance method, the benefits of

the proposed provision would come from the increased likelihood that a

cargo or baggage compartment fire would either be extinguished or

contained.

Section 23.1303 Flight and Navigation Instruments

Revised Sec. 23.1303(d) would add the requirement for a free air

temperature indicator for those airplanes whose performance must be

based on weight, altitude, and temperature. This requirement already

applies to turbine powered airplanes. The proposal would extend the

requirement to reciprocating engine powered airplanes of more than

6,000 pounds. Industry sources estimate that the proposed requirement

would cost an incremental $500 in engineering design per affected

airplane model and $350 per production airplane. Any additional weight

would be negligible. The potential benefits of the proposal would

accrue from the requirement that the information necessary to determine

the performance envelope of the airplane be available to the pilot.

Proposed Sec. 23.1303(g) would identify specific instruments, and

limits of those instruments, required for commuter category airplanes.

Proposed Sec. 23.1303(g)(1) states that if airspeed limitations vary

with altitude, the airspeed indicators must show the variation of the

maximum operating limit speed (VMO) with altitude. Industry

sources indicate that an airspeed indicator with VMO ``pointer''

would cost $1,000 more than one without. Two airspeed indicators are

required on commuter airplanes, therefore, the incremental cost of this

requirement would be $2,000 per commuter category airplane produced.

The potential safety benefit of the proposal would derive from the

requirement that the information necessary to determine the maximum

operating limit speed be available at all altitudes.

Proposed Sec. 23.1303(g)(3) would require (for commuter category

IFR-approved airplanes with passenger seating configurations of 10

more) a third, independent, attitude indicator (AI). Industry sources

estimate that an aerospace engineer could design and document a third

attitude instrument system in 100 hours at a burdened rate of $60 per

hour, totalling $6,000 per certification. It is estimated that an AI

would cost approximately $8,000, including a standby battery, and that

the installation would cost $2,200 for 40 hours of a mechanic's time at

a burdened rate of $55 per hour. However, proposed Sec. 23.1311(a)(5),

discussed below, would delete the requirement for a rate-of-turn

indicator when an independent attitude indicator is installed. The

costs associated with a rate-of-turn indicator include: 40 hours of

design and documentation costs, $1,000 per indicator, and 40 hours of

installation. Therefore, the incremental cost for an IFR-approved

airplane with a passenger seating capacity of 10 or more would be

$3,600 for 60 hours of engineering (100 hours for the AI, minus 40

hours for the rate-of-turn indicator); $7,000 for the instrument

($8,000 for the AI, minus $1,000 for the rate-of-turn indicator); and

no additional cost for the installation (40 hours for the AI, minus 40

hours for the rate-of-turn indicator).

The potential safety benefits of a third, independent attitude

indicator would derive from the reduced potential for erroneous

attitude information. Currently, two attitude instruments are required

for a ten passenger, IFR approved commuter category airplane. Service

experience has shown that a failure can occur whereby an attitude

indicator can appear to be working when it is actually providing

incorrect information. During such a failure, pilots may have

difficulty determining which instrument to follow, and hazardous flight

attitudes may result. A third attitude indicator would allow the crew

to retain reliable attitude information even in cases where one

instrument is not operating correctly.

Section 23. 1326 Pitot Heat Indication System

Proposed new G23.1326 would require the installation of a pitot

tube heat indicating system on those airplanes required to be equipped

with a heated pitot tube. Heated pitot tubes ensure that moisture will

not freeze in the tube and block or partially block the airspeed

system.

A pitot heat indicating system, including an in-line current

sensor, panel light, and associated wiring, would cost approximately

$500. According to industry sources, an aerospace engineer could design

and document such a system in 20 hours at a burdened rate of $60 per

hour, totalling $1,200. A mechanic could install the system in 20 hours

at a burden rate of $55 per hour, totalling $1,100. The estimated non-

recurring cost per certification, therefore, would total $2,800 ($1,200

for design, $500 for the certification airplane's indicator, and $1,100

for installation of that indicator). The estimated cost per production

airplane would be $1,600 ($500 for the system and $1,100 for

installation).

The National Transportation Safety Board (NTSB) investigated a

series of single model accidents that occurred between May 1989 and

March 1991. During that period, five fatal accidents and a near fatal

incident occurred in the United States. Two additional fatal accidents

involving the same airplane model occurred in foreign countries. The

NTSB's analysis indicated that four of the five U.S. accidents probably

involved ice blockage of the pitot tubes because the pilots failed to

activate pitot heat before flying into freezing instrument

meteorological conditions. The Board recommended (A-92-86) that the FAA

consider requiring a pitot heat operating light on small airplanes

certificated to operate in icing conditions.

A pitot heat indicating system would advise the pilots of any

inoperative heating element in the pitot tube and that subsequent

inaccuracies could result. The proposed provision would reduce the

likelihood that pilots would rely on inaccurate airspeed information

resulting from a blocked or partially blocked pitot tube.

Section 23.1353 Storage Battery Design and Installation

Proposed new Sec. 23.1353(h) would require that, in the event of a

complete loss of the primary electrical power generating system,

airplane battery capacity must be sufficient to supply at least 30

minutes of electrical power to those loads essential to the continued

safe flight and landing of the airplane.

In some cases, manufacturers may need to install larger batteries

with greater capacities to comply with the proposed requirements. The

FAA estimates that the size and capacity of a larger battery would add

no more than a few pounds (incremental operating costs of less than $10

per year) and $20 to $30 of additional cost for the battery.

On some airplanes, a ``load shedding'' procedure, where the pilot

would sequentially turn off certain equipment, could be required either

in place of or in addition to a larger battery. The procedure would be

provided in the pilot's operating handbook (POH). The FAA estimates

that an aerospace engineer could establish a load shedding procedure in

10 hours at a burdened rate of $60 per hour, for a total cost of $600

per affected certification.

Irrespective of the method of compliance, the proposal would

increase the likelihood that sufficient electrical power would be

available to safely land the airplane in the event of an electrical

generating system failure.

Section 23.1359 Electrical System Fire Protection.

Proposed Sec. 23.1359(c) would provide burn criteria for electrical

wire and cables. A proposed revision to appendix F to part 23 would add

appropriate wire testing criteria. Demonstrating and documenting that

electrical wires and cables meet the requirements of this provision

would take an aerospace engineer approximately 4 hours at a burdened

rate of $60 per hour, for a total of $240 per certification. The

requirement and testing criteria would increase the likelihood that

necessary wires and cables would continue to function in the event of a

fire.

Section 23.1365 Electrical Cables and Equipment

Proposed Sec. 23.1365(d) would add a requirement for the

identification of electrical cables, terminals, and connectors.

Different colored wires and/or tags could be used in conjunction with a

wiring diagram to identify the cables, terminals, and connectors. The

FAA estimates that a draftsman could design and document this

identification system in 80 hours at a burdened rate of $55 per hour, a

total of $4,400 per certification. Incremental installation costs would

be approximately $100 per airplane.

The increasing use of electrical systems in part 23 airplanes has

added to the difficultly of wiring installation. The proposed

requirement for cable identification would increase the likelihood that

cables would be correctly installed initially and would be correctly

reinstalled as part of later maintenance or modification.

Section 23.1401 Anticollision Light System

The proposal would revise Sec. 23.1401 to require the installation

of an anticollision light system on all part 23 airplanes. Current

Sec. 23.1401 requires an anticollision light system only if

certification for night operations is requested. Many manufacturers

currently install anticollision light systems on all airplanes they

produce.

Industry sources estimate that an aerospace engineer could design

and document an anticollision light system in 40 hours at a burdened

rate of $60 per hour, for a total of $2,400 per affected certification.

The system would cost $500 and would take a mechanic approximately 20

hours to install at a burdened rate of $55 per hour, a total of $1,600

per affected airplane ($500 + (20 hours x $55 per hour) = $1,600).

The weight penalty would be negligible. Only those future models that

would not otherwise have anticollision light systems would actually

incur incremental costs as a result of this provision.

The number of airplanes that have been added to the small airplane

fleet and the increasing speeds resulting from improved technology,

especially turbine engines, warrant the use of anticollision lights for

day operations as well as night. The FAA Accident and Incident data for

the period 1984 through 1990 show that 269 aircraft were involved in

midair collisions in which 108 fatalities occurred. When the data were

filtered (to account for night operations, IFR conditions, and aircraft

not affected by this proposal), it shows that at least 167 airplanes

were involved in accidents or incidents that occurred in day VFR

conditions. The reports do not reveal whether the airplanes were using

anticollision lights at the time of the accident.

The FAA holds that requiring the installation of anticollision

lights on all newly certificated airplanes, and requiring their

operation during day operations (as proposed by revised Sec. 91.209 and

discussed later in this evaluation), would reduce the number of

daylight, midair accidents. Even if the proposed requirement were only

25 percent effective, the 6-year accident history indicates that

approximately 17 fatalities could be avoided during a similar 6-year

period.

Section 23.1431 Electronic Equipment

This proposal would add three new paragraphs to Sec. 23.1431.

Proposed new paragraph (c) would require that airplanes required to be

operated by more than one flightcrew member must be evaluated to

determine if the flightcrew members can converse without difficulty

when they are seated at their duty stations. If the required evaluation

shows that the noise level does not impair conversation, no further

action would be required. If the evaluation shows that conversation

would be difficult, however, an intercommunication system would be

required.

The FAA estimates that an evaluation of cockpit noise could be

conducted in conjunction with other certification testing, therefore,

no incremental costs are associated with the evaluation. An aerospace

engineer could design an intercom system in 20 hours at a burdened rate

of $60 per hour, for a total of $1,200 per affected certification. The

FAA estimates that the addition of an intercom system would cost

approximately $500 per airplane. A mechanic could install the system in

approximately 20 hours at a burdened rate or $55 per hour. The total

incremental production cost for an affected airplane, therefore, would

be $1,600 ($500 + 20 hours x $55 per hour)).

Proposed new paragraph (d) would require that if the communication

equipment that is installed includes any means of switching from the

receive mode to the transmit mode, the equipment must use ``off-on''

transmitter switching that turns the transmitter off when it is not

being used. The cost of this feature is included in the $500 cost of

the intercom, described above.

NTSB investigation of at least two commuter accidents determined

that excessive cockpit noise levels probably adversely affected the

ability of the flight crews to communicate (Bar Harbor Airlines, Flight

1808, August 25, 1985, 8 fatalities; and Henson Airlines, Flight 1517,

September 23, 1985, 14 fatalities.)

As a result, the Board recommended (A-86-113) that the FAA require

the installation and use of crew interphone systems in the cockpit of

airplanes operating under part 135. The benefit of the proposed

requirement would derive from the increased likelihood that flightcrew

members would be able to converse without difficulty and that the

safety hazard of miscommunication would be reduced.

Section 23.1447 Equipment Standards for Oxygen Dispensing Units

Proposed new Sec. 23.1447(a)(4) would require that if radio

equipment is installed in an airplane, flightcrew oxygen dispensing

units must be designed to allow use of the communication equipment when

oxygen is being used.

Industry sources estimate that an oxygen mask with an integral

microphone costs $1,000 more than an oxygen mask without a microphone.

The costs per affected airplane, therefore, would be $2,000 for two

masks. The benefit of the proposed requirement is that it would allow

flightcrew communication under all operating conditions, including

operations when oxygen is required.

Section 23.1453 Protection of Oxygen Equipment From Rupture

This proposed new section would clarify the rupture protection

needed for oxygen system installation. Rupture protection for oxygen

systems is currently required by the application of the structures load

requirements of part 23. The addition of Sec. 23.1453(a) would clarify

the application of these load requirements and would identify the need

to consider maximum temperatures and pressures that may be present.

Section 23.1453(b) would identify the protection to be provided for

high pressure oxygen sources and the high pressure lines that connect

these sources to the oxygen system shutoff valves.

Industry sources estimate that an aerospace engineer could analyze

and document the loads on each element of the oxygen system in 16 hours

at a burdened rate of $60 per hour, for a total cost of $960. The

routing of oxygen pressure sources and lines to protect them from

unsafe temperatures and crash landings would be part of an airplane's

basic design and would not impose incremental costs.

Section 91.209 Aircraft Lights

Proposed new Sec. 91.209(b) would require airplanes equipped with

an anticollision light system to operate those lights during all

operations, including daytime VFR.

The incremental cost of this provision would be incurred for light

bulb replacement. The FAA estimates that a light bulb for an

anticollision light system costs approximately $50 and that this

provision would necessitate an incremental bulb replacement every two

years. Accordingly, the cost is projected to equal $25 per year, per

affected operating airplane.

In summary, the FAA holds that the benefits of the proposed rule,

though not directly quantifiable, would exceed the expected costs.

Regulatory Flexibility Determination

The Regulator Flexibility Act of 1980 (RFA) was enacted by Congress

to ensure that small entities are not unnecessarily or

disproportionately burdened by Government regulations. The RFA requires

a Regulatory Flexibility Analysis if a proposed rule would have a

significant economic impact, either detrimental or beneficial, on a

substantial number of small entities. FAA Order 2100.14A, Regulatory

Flexibility Criteria and Guidance, establishes threshold cost values

and small entity size standards for complying with RFA review

requirements in FAA rulemaking actions. The proposed amendments would

not have a significant economic impact on a substantial number of small

entities.

Trade Impact Assessment

The proposed rule would not constitute a barrier to international

trade, including the export of American goods and services to foreign

countries and the import of foreign goods and services into the United

States. Instead, the proposed systems airworthiness standards would be

harmonized with those of foreign aviation authorities and would lessen

the restraints on trade.

Federalism Implications

The regulations proposed herein would not have substantial direct

effects on the States, on the relationship between the national

government and the States, or on the distribution of power and

responsibilities among the various levels of government. Therefore, in

accordance with Executive Order 12612, it is determined that this

proposal would not have sufficient federalism implications to warrant

the preparation of a Federalism Assessment.

Conclusion

The FAA proposes to revise the airworthiness standards to provide

systems and equipment standards for normal, utility, acrobatic, and

commuter airplanes that are the same as the standards that will be

proposed for the same category airplanes by the Joint Aviation

Authorities in Europe. If adopted, the proposed revision would reduce

the regulatory burden on the United States and European airplane

manufacturers by relieving them on the need to show compliance with

different standards each time they seek certification approval of an

airplane in a different country.

For the reasons discussed in the preamble, and based on the

findings in the Regulatory Evaluation, the FAA has determined that this

proposed regulation is not significant under Executive Order 12866. In

addition, the FAA certifies that this proposal, if adopted, will not

have a significant economic impact, positive or negative, on a

substantial number of small entities under the criteria of the

Regulatory Flexibility Act. This proposal is not considered significant

under DOT Regulatory Policies and Procedures (44 FR 11034, February 26,

1979). An initial regulatory evaluation of the proposal has been placed

in the docket. A copy may be obtained by contacting the person

identified under FOR FURTHER INFORMATION CONTACT:

List of Subjects

14 CFR Part 23

Aircraft, Aviation safety, Signs and symbols.

14 CFR Part 91

Agriculture, Aircraft, Airmen, Airports, Air traffic control,

Aviation safety, Canada, Cuba, Freight, Mexico, Noise control,

Political candidates, Reporting and recordkeeping requirements, Safety,

Smoking.

The Proposed Amendment

In consideration of the foregoing, the Federal Aviation

Administration proposes to amend parts 23 and 91 of the Federal

Aviation Regulations (14 CFR part 23 and 91) as follows:

PART 23--AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND

COMMUTER CATEGORY AIRPLANES

1. The authority citation for part 23 continues to read as follows:

Authority: 49 U.S.C. app. 1344, 1354(a), 1355, 1421, 1423, 1425,

1428, 1429, 1430; 49 U.S.C. 106(g).

2. Section 23.677 is amended by revising paragraph (a) to read as

follows:

Sec. 23.677 Trim systems.

(a) Proper precautions must be taken to prevent inadvertent,

improper, or abrupt trim tab operation. There must be means near the

trim control to indicate to the pilot the direction of trim control

movement relative to airplane motion. In addition, there must be means

to indicate to the pilot the position of the trim device with respect

to both the range of adjustment and, in the case of lateral and

directional trim, the neutral position. This means must be visible to

the pilot and must be located and designed to prevent confusion. The

pitch trim indicator must be clearly marked with a position or range

within which it has been demonstrated that take-off is safe for all

center or gravity positions and each flap position approved for

takeoff.

* * * * *

3. A new Sec. 23.691 is added to read as follows:

Sec. 23.691 Artificial stall barrier system.

If the function of an artificial stall barrier, for example, stick

pusher, is necessary to show compliance with Sec. 23.201(c), the system

must comply with the following:

(a) With the system adjusted for operation, the plus and minus

airspeeds at which downward pitching control will be provided must be

established.

(b) Considering the plus and minus airspeed tolerances established

by paragraph (a) of this section, and airspeed must be selected for the

activation of the downward pitching control that provides a safe margin

above any airspeed at which any unsatisfactory stall characteristics

occur.

(c) In addition to the stall warning required by Sec. 23.207, a

warning that is clearly distinguishable to the pilot under all expected

flight conditions without requiring the pilot's attention, must be

provided for faults that would prevent the system from providing the

required pitching motion.

(d) Each system must be designed so that the artificial stall

barrier can be quickly and positively disengaged by the pilots to

prevent unwanted downward pitching of the airplane by a quick release

(emergency) control that meets the requirements of Sec. 23.1329(b).

(e) A preflight check of the complete system must be established

and the procedure for this check made available in the Airplane Flight

Manual (AFM). Preflight checks that are critical to the safety of the

airplane must be included in the limitations section of the AFM.

(f) For those airplanes whose design includes an autopilot system:

(1) A quick release (emergency) control installed in accordance

with Sec. 23.1329(b) may be used to meet the requirements of paragraph

(d) of this section, and

(2) The pitch servo for that system may be used to provide the

stall downward pitching motion.

(g) In showing compliance with Sec. 23.1309, the system must be

evaluated to determine the effect that any announced or unannounced

failure may have on the continued safe flight and landing of the

airplane or the ability of the crew to cope with any adverse conditions

that may result from such failures. This evaluation must consider the

hazards that would result from the airplane's flight characteristics if

the system was not provided, and the hazard that may result from

unwanted downward pitching motion, which could result from failures at

airspeeds above the selected stall speed.

4. Section 23.697 is amended by adding a new paragraph (c) to read

as follows:

Sec. 23.697 Wing flap controls.

* * * * *

(c) If compliance with Sec. 23.145(b)(3) necessitates wing flap

retraction to positions that are not fully retracted, the wing flap

control lever settings corresponding to those positions must be

positively located such that a definite change of direction of movement

of the lever is necessary to select settings beyond those settings.

5. Section 23.701 is amended by revising paragraphs (a)(1) and

(a)(2) to read as follows:

Sec. 23.701 Flap interconnection.

(a) * * *

(1) Be synchronized by a mechanical interconnection between the

movable flap surfaces that is independent of the flap drive system; or

by an approved equivalent means; or

(2) Be designed so that the occurrence of any failure of the flap

system that would result in an unsafe flight characteristic of the

airplane is extremely improbable; or

* * * * *

6. A new Sec. 23.703 is added to read as follows:

Sec. 23.703 Takeoff warning system.

For commuter category airplanes, unless it can be shown that a lift

or longitudinal trim device which affects the takeoff performance of

the aircraft would not give an unsafe takeoff configuration when

selected out of an approved takeoff position, a takeoff warning system

must be installed and meet the following requirements:

(a) The system must provide to the pilots an aural warning that is

automatically activated during the initial portion of the takeoff roll

if the airplane is in a configuration that would not allow a safe

takeoff. The warning must continue until--

(1) The configuration is changed to allow safe takeoff, or

(2) Action is taken by the pilot to abandon the takeoff roll.

(b) The means used to activate the system must function properly

for all authorized takeoff power settings and procedures and throughout

the ranges of takeoff weights, altitudes and temperatures for which

certification is requested.

Sec. 23.723 [Amended]

7. Section 23.723(b) is amended by changing the word ``reserved''

to ``reserve''.

8. Section 23.729 is amended by revising paragraph (e) and by

adding a new paragraph (g) to read as follows:

Sec. 23.729 Landing gear extension and retraction system.

* * * * *

(e) Position indicator. If a retractable landing gear is used,

there must be a landing gear position indicator (as well as necessary

switches to actuate the indicator) or other means to inform the pilot

that each gear is secured in the extended (or retracted) position. If

switches are used, they must be located and coupled to the landing gear

mechanical system in a manner that prevents an erroneous indication of

either ``down and locked'' if each gear is not in the fully extended

position, or of ``up and locked'' if each landing gear is not in the

fully retracted position.

* * * * *

(g) Equipment located in the landing gear bay. If the landing gear

bay is used as the location for equipment other than the landing gear,

that equipment must be designed and installed to minimize damage.

9. Section 23.735 is amended by redesignating paragraph (c) as

paragraph (d), by revising the introductory text of paragraph (a), and

by adding new paragraphs (c) and (e) to read as follows:

Sec. 23.735 Brakes.

(a) Brakes must be provided. The landing brake kinetic energy

capacity rating of each main wheel brake assembly must not be less than

the kinetic energy absorption requirements determined under either of

the following methods:

* * * * *

(c) During the landing distance determination required by

Sec. 23.75, the pressure on the wheel braking system must not exceed

the pressure specified by the brake manufacturer.

* * * * *

(e) In addition, for commuter category airplanes, the rejected

takeoff brake kinetic energy capacity rating of each main wheel brake

assembly must not be less than the kinetic energy absorption

requirements determined under either of the following methods--

(1) The brake kinetic energy absorption requirements must be based

on a conservative rational analysis of the sequence of events expected

during a rejected takeoff at the design takeoff weight.

(2) Instead of a rational analysis, the kinetic energy absorption

requirements for each main wheel brake assembly may be derived from the

following formula--

KE=0.0443 WV\2\/N

where,

KE=Kinetic energy per wheel (ft.-lbs.);

W=Design takeoff weight (lbs.);

V=Ground speed associated with the maximum value of V1 selected in

accordance with Sec. 23.51(c)(1);

N=Number of main wheels with brakes.

10. A new Sec. 23.745 is added to read as follows:

Sec. 23.745 Nose/tail wheel steering.

(a) If nose/tail wheel steering is installed, it must be

demonstrated that its use does not require exceptional pilot skill

during takeoff and landing, in crosswinds and in the event of an engine

failure; or its use must be limited to low speed maneuvering.

(b) Movement of the pilot's steering control must not interfere

with the retraction or extension of the landing gear.

11. Section 23.775 is amended by revising paragraphs (a) and (c),

by redesignating paragraph (d) as (e) and paragraph (e) as (d), by

revising the newly designated paragraph (e), and by adding a new

paragraph (h) to read as follows:

Sec. 23.775 Windshields and windows.

(a) The internal panels of windshields and windows must be

constructed of a nonsplintering material, such as nonsplintering safety

glass.

* * * * *

(c) On pressurized airplanes, if certification for operation up to

and including 25,000 feet is requested, an enclosure canopy including a

representative part of the installation must be subjected to special

tests to account for the combined effects of continuous and cyclic

pressurization loadings and flight loads, or compliance with the fail-

safe requirements of paragraph (d) of this section must be shown.

* * * * *

(e) The windshield and side windows forward of the pilot's back

when the pilot is seated in the normal flight position must have a

luminous transmittance value of not less than 70 percent.

* * * * *

(h) In addition, for commuter category airplanes, the following

applies:

(1) Windshield panes directly in front of the pilots in the normal

conduct of their duties, and the supporting structures for these panes

must withstand, without penetration, the impact of a two-pound bird

when the velocity of the airplane (relative to the bird along the

airplane's flight path) is equal to the airplane's maximum approach

flap speed.

(2) The windshield panels in front of the pilots must be arranged

so that, assuming the loss of vision through any one panel, one or more

panels remain available for use by a pilot seated at a pilot station to

permit continued safe flight and landing.

12. Section 23.783 is amended by revising paragraph (b) and by

adding a new paragraph (g) to read as follows:

Sec. 23.783 Doors.

* * * * *

(b) Passenger doors must not be located with respect to any

propeller disk or any other potential hazard so as to endanger persons

using that door.

* * * * *

(g) If lavatory doors are installed, they must be designed to

preclude an occupant from becoming trapped inside the lavatory. If a

locking mechanism is installed, it must be capable of being unlocked

from outside of the lavatory.

13. Section 23.785 is amended by adding introductory text and by

revising paragraph (b) to read as follows:

Sec. 23.785 Seats, berths, litters, safety belts and shoulder

harnesses.

There must be a seat or berth for each occupant that meets the

following:

* * * * *

(b) Each forward-facing or aft-facing seat/restraint system in

normal, utility, or acrobatic category airplanes must consist of a

seat, a safety belt, and a shoulder harness, with a metal-to-metal

latching device as required by Sec. 23.1413, that are designed to

provide the occupant protection provisions required in Sec. 23.562.

Other seat orientations must provide the same level of occupant

protection as a forward-facing or aft-facing seat with a safety belt

and a shoulder harness, and must provide the protection provisions of

Sec. 23.562.

* * * * *

14. Section 23.787 is revised to read as follows:

Sec. 23.787 Baggage and cargo compartments.

(a) Each baggage and cargo compartment must:

(1) Be designed for its placarded maximum weight of contents and

for the critical load distributions at the appropriate maximum load

factors corresponding to the flight and ground load conditions of this

part.

(2) Have means to prevent the contents of any compartment from

becoming a hazard by shifting, and to protect any controls, wiring,

lines, equipment or accessories whose damage or failure would affect

safe operations.

(3) Have a means to protect occupants from injury by the contents

of any compartment, located aft of the occupants and separated by

structure, when the ultimate forward inertial load factor is 9g and

assuming the maximum allowed baggage or cargo weight for the

compartment.

(b) Designs that provide for baggage or cargo to be carried in the

same compartment as passengers must have a means to protect the

occupants from injury when the baggage or cargo is subjected to the

inertial loads resulting from the ultimate static load factors of

Sec. 23.561(b)(3), assuming the maximum allowed baggage or cargo weight

for the compartment.

(c) For airplanes that are used only for the carriage of cargo, the

flightcrew emergency exits must meet the requirements of Sec. 23.807

under any cargo loading conditions.

15. A new Sec. 23.791 is added to read as follows:

Sec. 23.791 Passenger information signs.

For those airplanes in which the flightcrew members cannot observe

the other occupants' seats or where the flightcrew members' compartment

is separated from the passenger compartment, there must be at least one

illuminated sign (using either letters or symbols) notifying all

passengers when seat belts should be fastened. Signs that notify when

seat belts should be fastened must:

(a) When illuminated, be legible to each person seated in the

passenger compartment under all probable lighting conditions; and

(b) Be installed so that a flightcrew member can, when seated at

the flightcrew member's station, turn the illumination on and off.

16. Section 23.807 is amended by revising paragraphs (b)

introductory text and (b)(5) and by adding new paragraphs (a)(4) and

(b)(6) to read as follows:

Sec. 23.807 Emergency exits.

(a) * * *

(4) Emergency exits must not be located with respect to any

propeller disk or any other potential hazard so as to endanger persons

using that exit.

(b) Type and operation. Emergency exits must be movable windows,

panels, canopies, or external doors, openable from both inside and

outside the airplane, that provide a clear and unobstructed opening

large enough to admit a 19-by-26-inch ellipse. Auxiliary locking

devices used to secure the airplane must be designed to be overridden

by the normal internal opening means. The inside handles of emergency

exits that open outward must be adequately protected against

inadvertent operation. In addition, each emergency exit must--

* * * * *

(5) In the case of acrobatic category airplanes, allow each

occupant to abandon the airplane at any speed between VSO and

VD; and

(6) In the case of utility category airplanes certificated for

spinning, allow each occupant to abandon the airplane at the highest

speed likely to be achieved in the maneuver for which the airplane is

certificated.

* * * * *

Sec. 23.841 [Amended]

17. Section 23.841 is amended in paragraph (a) by removing the

number ``31,000'' and replacing it with ``25,000''.

18. Section 23.853 is amended by revising the section heading to

read as follows:

Sec. 23.853 Passenger and crew compartment interiors.

* * * * *

19. A new Sec. 23.855 is added to read as follows:

Sec. 23.855 Cargo and baggage compartment fire protection.

(a) Sources of heat within each cargo and baggage compartment that

are capable of igniting the compartment contents must be shielded and

insulated to prevent such ignition.

(b) Each cargo and baggage compartment must be constructed of

materials that meet the appropriate provisions of Sec. 23.853(d)(3).

(c) In addition for commuter category airplanes, each cargo and

baggage compartment must:

(1) Be located where the presence of a fire would be easily

discovered by the pilots when seated at their duty station, or it must

be equipped with a smoke or fire detector system to give a warning at

the pilots' station, and provide sufficient access to enable a pilot to

effectively reach any part of the compartment with the contents of a

hand held fire extinguisher, or

(2) Be equipped with a smoke or fire detector system to give a

warning at the pilots' station and have ceiling and sidewall liners and

floor panels constructed of materials that have been subjected to and

meet the 45 degree angle test of Appendix F of this part. The flame may

not penetrate (pass through) the material during application of the

flame or subsequent to its removal. The average flame time after

removal of the flame source may not exceed 15 seconds, and the average

glow time may not exceed 10 seconds. The compartment must be

constructed to provide fire protection that is not less than that

required of its individual panels; or

(3) Be constructed and sealed to contain any fire within the

compartment.

20. Section 23.867 is amended by revising the heading that precedes

the section and the section heading to read as follows:

Electrical Bonding and Lightning Protection

Sec. 23.867 Electrical bonding and protection against lightning and

static electricity.

* * * * *

21. Section 23.1303 is amended by revising the introductory text;

by amending paragraph (d) by inserting the words ``reciprocating

engine-powered airplanes of more than 6,000 pounds maximum weight and''

between the words ``For'' and ``turbine''; by amending paragraph (e)

concluding text by adding a line to read, ``The lower limit of the

warning device must be set to minimize nuisance warning;'' at the end

of the paragraph and by adding new paragraphs (f) and (g) to read as

follows:

Sec. 23.1303 Flight and navigation instruments.

The following are the minimum required flight and navigation

instruments:

* * * * *

(f) When an attitude display is installed, the instrument design

must not provide any means, accessible to the flightcrew, of adjusting

the relative positions of the attitude reference symbol and the horizon

line beyond that necessary for parallax correction.

(g) In addition, for commuter category air planes:

(1) If airspeed limitations vary with altitude, the airspeed

indicator must have a maximum allowable airspeed indicator showing the

variation of VMO with altitude.

(2) The altimeter must be a sensitive type.

(3) Having a passenger seating configuration of 10 or more,

excluding the pilot's seats and that are approved for IFR operations, a

third attitude instrument must be provided that:

(i) Is powered from a source independent of the electrical

generating system;

(ii) Continues reliable operation for a minimum of 30 minutes after

total failure of the electrical generating system;

(iii) Operates independently of any other attitude indicating

system;

(iv) Is operative without selection after total failure of the

electrical generating system;

(v) Is located on the instrument panel in a position acceptable to

the Administrator that will make it plainly visible to and usable by

any pilot at the pilot's station; and

(vi) Is appropriately lighted during all phases of operation.

Sec. 23.1307 [Amended]

22. Section 23.1307 is amended by removing paragraphs (a) and (b);

and by removing the designation from paragraph (c).

23. Section 23.1309 is amended by adding a new paragraph (a)(4) to

read as follows:

Sec. 23.1309 Equipment, systems, and installations.

(a) * * *

(4) In a commuter category airplane, must be designed to safeguard

against hazards to the airplane in the event of their malfunction or

failure.

* * * * *

24. Section 23.1311 is revised to read as follows:

Sec. 23.1311 Electronic display instrument systems.

(a) Electronic display indicators, including those with features

that make isolation and independence between powerplant instrument

systems impractical, must:

(1) Meet the arrangement and visibility requirements of

Sec. 23.1321.

(2) Be easily legible under all lighting conditions encountered in

the cockpit, including direct sunlight, considering the expected

electronic display brightness level at the end of an electronic display

indicator's useful life. Specific limitations on display system useful

life must be contained in the Instructions for Continued Airworthiness

required by Sec. 23.1529.

(3) Not inhibit the primary display of attitude, airspeed,

altitude, or powerplant parameters needed by any pilot to set power

within established limitations, in any normal mode of operation.

(4) Not inhibit the primary display of engine parameters needed by

any pilot to properly set or monitor powerplant limitations during the

engine starting mode of operation.

(5) Have an independent magnetic direction indicator and either an

independent secondary mechanical altimeter, airspeed indicator, and

attitude instrument or individual electronic display indicators for the

altimeter, airspeed, and attitude indicator that are independent from

the airplane's primary electrical power system. These secondary

instruments may be installed in panel positions that are displaced from

the primary positions specified by Sec. 23.1321(d), but must be located

where they meet the pilots' visibility requirements of Sec. 23.1321(a).

(6) Incorporate sensory cues for the pilot that are equivalent to

those in the instrument being replaced by the electronic display

indicators.

(7) Incorporate visual displays of instrument markings, required by

Secs. 23.1541 through 23.1553, or visual displays that alert the pilot

to abnormal operational values or approaches to established limitation

values, for each parameter required to be displayed by this part.

(b) The electronic display indicators, including their systems and

installations, and considering other airplane systems, must be designed

so that one display of information essential for continued safe flight

and landing will remain available to the crew, without need for

immediate action by any pilot for continued safe operation, after any

single failure or probable combination of failures.

(c) As used in this section, ``instrument'' includes devices that

are physically contained in one unit, and devices that are composed of

two or more physically separate units or components connected together

(such as a remote indicating gyroscopic direction indicator that

includes a magnetic sensing element, a gyroscopic unit, an amplifier,

and an indicator connected together). As used in this section,

``primary'' display refers to the display of a parameter that is

located in the instrument panel such that the pilot looks at it first

when wanting to view that parameter.

Sec. 23.1321 [Amended]

25. Section 23.1321 is amended by removing the words ``certificated

for flight under instrument flight rules or of more than 6,000 pounds

maximum weight'' from paragraph (d) introductory test.

26. Section 23.1323 is amended by redesignating paragraph (c) as

(e); by removing paragraph (d); by redesignating paragraph (e) as new

paragraph (d); by removing the words ``in flight and'' from the first

sentence of redesignated paragraph (e); and by adding new paragraphs

(c) and (f) to read as follows:

Sec. 23.1323 Airspeed indicating system.

* * * * *

(c) The design and installation of each airspeed indicating system

must provide positive drainage of moisture from the pitot static

plumbing.

* * * * *

(f) For commuter category airplanes, where duplicate airspeed

indicators are required, their respective pitot tubes must be far

enough apart to avoid damage to both tubes in a collision with a bird.

Sec. 23.1325 [Amended]

27. Section 23.1325 is amended by inserting the words ``or icing''

between the words ``meteorological'' and ``conditions'' in paragraph

(g).

28. A new Sec. 23.1326 is added to read as follows:

Sec. 23.1326 Pitot heat indication systems.

If a flight instrument pitot heating system is installed to meet

the requirements specified in Sec. 23.1323(d), an indication system

must be provided to indicate to the flight crew when that pitot heating

system is not operating. The indication system must comply with the

following requirements:

(a) The indication provided must incorporate an amber light that is

in clear view of a flightcrew member.

(b) The indication provided must be designed to alert the flight

crew if either of the following conditions exist:

(1) The pitot heating system is switched ``off''.

(2) The pitot heating system is switched ``on'' and any pitot tube

heating element is inoperative.

Sec. 23.1329 [Amended]

29. Section 23.1329(b) is amended by adding the parenthetical

phrase ``(both stick controls, if the airplane can be operated from

either pilot seat)'' between the words, ``or on the stick control,''

and the word ``such''.

30. Section 23.1337 is amended by revising the section heading, by

revising the introductory text of paragraph (b), by redesignating

paragraphs (b)(4) and (b)(5) as paragraph (b)(5) and (b)(6),

respectively, and by adding a new paragraph (b)(4) to read as follows:

Sec. 23.1337 Powerplant instruments installation.

* * * * *

(b) Fuel quantity indication. There must be a means to indicate to

the flightcrew members the quantity of usable fuel in each tank during

flight. An indicator calibrated in appropriate units and clearly marked

to indicate those units must be used. In addition:

* * * * *

(4) There must be a means to indicate the amount of usable fuel in

each tank when the airplane is on the ground (such as by a stick

gauge);

* * * * *

31. Section 23.1351 is amended by removing paragraph (b)(4), by

redesignating paragraphs (b)(5) as (b)(4), by adding a sentence to the

end of paragraph (f) that reads, ``The external power connection must

be located so that its use will not result in a hazard to the airplane

or ground personnel'', and by revisiting paragraphs (b)(2), (b)(3), and

(c)(3) to read as follows:

Sec. 23.1351 General.

* * * * *

(b) * * *

(2) Electric power source must function properly when connected in

combination or independently.

(3) No failure or malfunction of any electric power source may

impair the ability of any remaining source to supply load circuits

essential for safe operation.

* * * * *

(c) * * *

(3) Automatic means must be provided to prevent either damage to

any generator/alternator or adverse effects on the airplane electrical

system due to reverse current. A means must also be provided to

disconnect each generator/alternator from the battery and other

generators/alternators.

* * * * *

32. Section 23.1353 is amended by adding a new paragraph (h) to

read as follows:

Sec. 23.1353 Storage battery design and installation.

* * * * *

(h) In the event of a complete loss of the primary electrical power

generating system, the battery must be capable of providing at least 30

minutes of electrical power to those loads that are essential to

continue safe flight and landing. The 30 minute time period includes

the time needed for the pilots to recognize the loss of generated power

and take appropriate load shedding action.

33. A new Sec. 23.1359 is added to read as follows:

Sec. 23.1359 Electrical system fire protection.

(a) Each component of the electrical system must meet the

applicable fire protection requirement of Secs. 23.863 and 23.1182.

(b) Electrical cables, terminals, and equipment in designated fire

zones that are used during emergency procedures must be fire-resistant.

(c) Insulation on electrical wire and electrical cable must be

self-extinguishing when tested at an angle of 60 degrees in accordance

with the applicable portions of Appendix F of this part, or other

approved equivalent methods. The average burn length must not exceed 3

inches (76 mm) and the average flame time after removal of the flame

source must not exceed 30 seconds. Drippings from the test specimen

must not continue to flame for more than an average of 3 seconds after

falling.

Sec. 23.1361 [Amended]

34. Section 23.1361(c) is amended by removing the last two words

``in flight''.

35. Section 23.1365 is amended by revising paragraph (b) and by

adding new paragraphs (d), (e), and (f) to read as follows:

Sec. 23.1365 Electrical cables and equipment.

* * * * *

(b) Any equipment that is associated with any electrical cable

installation and that would overheat in the event of circuit overload

or fault must be flame resistant. The equipment and the electrical

cables must not emit dangerous quantities of toxic fumes.

* * * * *

(d) Means of identification must be provided for electrical cables,

terminals, and connectors.

(e) Electrical cables must be installed such that the risk of

mechanical damage and/or damage caused by fluids, vapors, or sources of

heat, is minimized.

(f) Where a cable cannot be protected by a circuit protection

device or other overload protection, it must not cause a fire hazard

under fault conditions.

36. Section 23.1383 is revised to read as follows:

Sec. 23.1383 Taxi and landing lights.

Each taxi and landing light must be designed and installed so that:

(a) No dangerous glare is visible to the pilots.

(b) The pilot is not seriously affected by halation.

(c) It provides enough light for night operations.

(d) It does not cause a fire hazard in any configuration.

37. Section 23.1401 is amended by revising the introductory text of

paragraph (a) to read as follows:

Sec. 23.1401 Anticollision light system.

(a) General. The airplane must have an anticollision light system

that:

* * * * *

38. Section 23.1431 is amended by adding new paragraphs (c), (d),

and (e) to read as follows:

Sec. 23.1431 Electronic equipment.

* * * * *

(c) For those airplanes required to have more than one flightcrew

member, or whose operation will require more than one flightcrew

member, the cockpit must be evaluated to determine if the flightcrew

members, when seated at their duty station, can converse without

difficulty. If the airplane design includes provision for the use of

communication headsets, the evaluation must also consider conditions

where headsets are being used. If the evaluation shows conditions under

which it will be difficult to converse, an intercommunication system

must be provided.

(d) If installed communication equipment includes transmitter

``off-on'' switching, that switching means must be designed to return

from the ``transmit'' to the ``off'' position when it is released and

ensure that the transmitter will return to the off (non transmitting)

state.

(e) If provisions for the use of communication headsets are

provided, it must be demonstrated that the flightcrew members will

receive all aural warnings when any headset is being used.

39. Section 23.1435 is amended by revising paragraph (c) to read as

follows:

Sec. 23.1435 Hydraulic systems.

* * * * *

(c) Accumulators. A hydraulic accumulator or reservoir may be

installed on the engine side of any firewall if--

(1) It is an integral part of an engine or propeller system, or

(2) The reservoir is nonpressurized and the total capacity of all

such nonpressurized reservoirs is one quart or less.

40. Section 23.1447 is amended by revising paragraphs (d) and (e)

and by adding a new paragraph (a)(4) to read as follows:

Sec. 23.1447 Equipment standards for oxygen dispensing units.

* * * * *

(a) * * *

(4) If radio equipment is installed, the flightcrew oxygen

dispensing units must be designed to allow the use of that equipment

and to allow communication with any other required crew member while at

their assigned duty station.

* * * * *

(d) For a pressurized airplane designed to operate at flight

altitudes above 25,000 feet (MSL), the dispensing units must meet the

following:

(1) The dispensing units for passengers must be connected to an

oxygen supply terminal and be immediately available to each occupant

wherever seated.

(2) The dispensing units for crewmembers must be automatically

presented to each crewmember before the cabin pressure altitude exceeds

15,000 feet, or the units must be of the quick-donning type, connected

to an oxygen supply terminal that is immediately available to

crewmembers at their station.

(e) If certification for operation above 30,000 feet is requested,

the dispensing units for passengers must be automatically presented to

each occupant before the cabin pressure altitude exceeds 15,000 feet.

* * * * *

41. A new Sec. 23.1451 is added to read as follows:

Sec. 23.1451 Fire protection for oxygen equipment.

Oxygen equipment and lines must:

(a) Not be installed in any designated fire zones.

(b) Be protected from heat that may be generated in, or escape

from, any designated fire zone.

(c) Be installed so that escaping oxygen cannot come in contact

with and cause ignition of grease, fluid, or vapor accumulations that

are present in normal operation or that may result from the fa

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