# Certification of Turbojets

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3AE9-19350

## Record

- **Collection:** Federal Register
- **Document type:** Proposed Rule
- **Published:** August 17, 2009
- **Citation:** 74 FR 41522

## Text

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Parts 1 and 23
[Docket No. FAA-2009-0738; Notice No. 09-09]
RIN 2120-AJ22
Certification of Turbojets

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This action proposes to enhance safety by amending the applicable standards for part 23 turbojet-powered airplanes—which are commonly referred to as “turbojets”—to reflect the current needs of industry, accommodate future trends, address emerging technologies, and provide for future airplane operations. This action is necessary to eliminate the current workload of processing exemptions, special conditions, and equivalent levels of safety findings necessary to certificate light part 23 turbojets. The intended effect of the proposed changes would: Standardize and simplify the certification of part 23 turbojets; clarify areas of frequent non-standardization and misinterpretation, particularly for electronic equipment and system certification; and codify existing certification requirements in special conditions for new turbojets that incorporate new technologies.

DATES:

Send your comments on or before November 16, 2009.

ADDRESSES:

You may send comments identified by Docket Number FAA-2009-0738 using any of the following methods:

•
Federal eRulemaking Portal:
Go to
http://www.regulations.gov
and follow the online instructions for sending your comments electronically.

•
Mail:
Send comments to Docket Operations, M-30, U.S. Department of Transportation, 1200 New Jersey Avenue, SE., Room W12-140, West Building Ground Floor, Washington, DC 20590-0001.

•
Hand Delivery or Courier:
Bring comments to Docket Operations in Room W12-140 of the West Building Ground Floor at 1200 New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

•
Fax:
Fax comments to Docket Operations at 202-493-2251.

For more information on the rulemaking process,
see
the
SUPPLEMENTARY INFORMATION
section of this document.

Privacy:
We will post all comments we receive, without change, to
http://www.regulations.gov
, including any personal information you provide. Using the search function of our docket Web site, anyone can find and read the electronic form of all comments received into any of our dockets, including the name of the individual sending the comment (or signing the comment for an association, business, labor union, etc.). You may review DOT's complete Privacy Act Statement in the
Federal Register
published on April 11, 2000 (65 FR 19477-78) or you may visit
http://DocketsInfo.dot.gov.

Docket:
To read background documents or comments received, go to
http://www.regulations.gov
at any time and follow the online instructions for accessing the docket. Or, go to Docket Operations in Room W12-140 of the West Building Ground Floor at 1200 New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT:

For technical questions concerning this proposed rule, contact Pat Mullen, Regulations and Policy, ACE-111, Federal Aviation Administration, 901 Locust St., Kansas City, MO 64106;
telephone:
(816) 329-4111; facsimile (816) 329-4090;
e-mail: pat.mullen@faa.gov.
For legal questions concerning this proposed rule, contact Mary Ellen Loftus, ACE-7, Federal Aviation Administration, 901 Locust St., Kansas City, MO 64106;
telephone:
(816) 329-3764;
e-mail: mary.ellen.loftus@faa.gov.

SUPPLEMENTARY INFORMATION:

Later in this preamble under the Additional Information section, we discuss how you can comment on this proposal and how we will handle your comments. Included in this discussion is related information about the docket, privacy, and the handling of proprietary or confidential business information. We also discuss how you can get a copy of this proposal and related rulemaking documents.

Authority for This Rulemaking

The FAA's authority to issue rules on aviation safety is found in Title 49 of the United States Code. Subtitle I, Section 106 describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs describes in more detail the scope of the agency's authority.

This rulemaking is promulgated under the authority described in Subtitle VII, Part A, Subpart III, Section 44701. Under that section, the FAA is charged with promoting safe flight of civil airplanes in air commerce by prescribing minimum standards required in the interest of safety for the design and performance of airplanes. This regulation is within the scope of that authority because it prescribes new safety standards for the design of normal, utility, acrobatic, and commuter category airplanes.

Table of Contents

I. Background

A. Historical Certification Requirements Overview

B. Aviation Rulemaking Committee (ARC) Recommendations

C. Proposed Regulatory Requirements Overview

II. Discussion of the Proposed Regulatory Requirements

III. Regulatory Notices and Analyses

IV. The Proposed Amendments

I. Background

A. Historical Certification Requirements Overview

Title 14 Code of Federal Regulations (14 CFR) part 23 provides the airworthiness standards for Normal, Utility, Acrobatic, and Commuter Category Airplanes. The first application for the certification of a turbojet airplane under part 23 occurred in the 1970s before many of the current turbine requirements were added to part 23. Prior to this, turbojet powered airplanes were certificated to the standards under part 25. Part 25 provides the airworthiness standards for Transport category airplanes. A turbojet is a jet engine that develops thrust using a turbine compressor which is propelled by high speed exhaust gases expelled as a jet. The FAA implemented many of the certification requirements for early part 23 turbojets through special conditions based on 14 CFR part 25 (pre-amendment 25-42, (43 FR 2320)) requirements. Almost all special conditions applied to turbojets were for part 23, subpart B, Flight, and subpart G, Operating Limitations and Information.

Special conditions for part 23 certification increased performance requirements for emerging turbojets similar to those covered by early part 25 standards. The FAA established these special conditions to ensure a minimum one-engine inoperative (OEI) performance level that would be included in the airplane's limitations, thereby guaranteeing single-engine climb performance. The level of safety provided by the special conditions was purposely higher for the early turbojets than for propeller-driven airplanes in the same weight band because the manufacturers and the FAA wanted part 23 turbojets to be similar to part 25

business jets. Special conditions also addressed the following safety concerns: (1) The lack of turbine requirements in part 23, (2) the sensitivity of turbine engines to altitude and temperature effects, and (3) the high takeoff and landing speeds associated with turbojets that typically required long takeoff and landing distances, as compared to the performance of reciprocating, multiengine airplanes of that era.

In the mid-1990s, the FAA hosted a meeting for flight test pilot representatives from the Aircraft Certification Offices. The purpose of that meeting was to discuss how emerging 600 to 1,200 pound thrust engines were being developed and how the FAA would certificate future turbojet programs. The participants considered the prospect for small single- and multi-engine turbojets. At that time, the FAA assumed that any new part 23 turbojet would have similar characteristics to any existing small part 25 turbojet. However, using the preliminary design estimates from several new turbojets, FAA flight test personnel realized these assumptions were outdated. Therefore, the FAA needed to reevaluate its certification standards for turbojets against existing light-weight airplanes.

The meeting participants did not want to discourage development of small part 23 turbojets by applying significantly higher standards than for an equivalent propeller airplane. Therefore, the participants decided the best approach for future turbojet certification programs was to apply the existing part 23 weight differentiator of 6,000 pounds in establishing requirements.

B. Aviation Rulemaking Committee (ARC) Recommendations

On February 3, 2003, we published a notice announcing the creation of the part 125/135 Aviation Rulemaking Committee.
1

Part 125 addresses the certification and operations of airplanes having a seating capacity of 20 or more passengers or a maximum payload capacity of 6,000 pounds or more. Part 135 addresses the operating requirements for commuter and on-demand operations and rules governing persons on board such aircraft. Since some part 23 airplanes operate under parts 125 or 135, the ARC provided recommendations to the FAA for safety standards applicable for part 23 turbojet airplanes to reflect the current industry, industry trends, emerging technologies and operations under parts 125 and 135, and associated regulations. The ARC also reviewed the existing part 23 certification requirements and the accident history of light piston-powered, multiengine airplanes up through small turbojets used privately and for business. In addition, the ARC reviewed the special conditions applied to part 23 turbojets. The ARC completed its work in 2005 and submitted its recommendations to the FAA. Those documents may be reviewed in the docket for this proposed rule. The ARC recommended modifying forty-one 14 CFR part 23 sections as a result of its review of these areas.

1
68 FR 5488

As stated earlier, the FAA's intent is to codify standards consistent with the level of safety currently required through special conditions. We compared the special conditions applied to part 23 turbojets, as well as several additional proposed part 23 changes, with the ARC's recommendations. With few exceptions, the ARC recommendations validated the FAA's long-held approach to certification of part 23 turbojets.

The ARC did not want to impose commuter category takeoff speeds for turbojets above 6,000 pounds, nor did the ARC want to impose more stringent requirements for one-engine inoperative (OEI) climb performance than those established for similar-sized piston-powered and turboprop multiengine airplanes. The FAA ultimately accepted thirty-nine of the forty-one ARC recommendations and developed this proposed rulemaking in accordance with them. The two recommendations we disagreed with would have lowered the standards previously applied through special conditions.

C. Proposed Regulatory Requirements Overview

The FAA currently issues type certificates (TCs) to part 23 turbojets using extensive special conditions, exemptions, and equivalent levels of safety (ELOS). Until recently, this practice of using special conditions, exemptions, and ELOS did not represent a significant workload because there were relatively few part 23 turbojet programs. However, in the past five years, the number of new part 23 turbojet type certification programs has increased more than 100 percent over the program numbers of the past three decades. The need to incorporate special conditions, exemptions, and ELOS into part 23 stems from this rise in the number of new turbojet programs and the expected growth in the number of future programs. Codifying special conditions would standardize and clarify the requirements for manufacturers during the design phase of turbojets. Doing so would prevent instances where manufacturers design turbojets and later have to demonstrate compliance with special conditions that may require redesign. Codifying special conditions, exemptions, and ELOS would also eliminate the manufacturers' and the FAA's workload associated with processing these documents and could reduce potential delays to project schedules. Many of the proposed changes in this notice would codify certification requirements and practices currently accomplished through use of special conditions, exemptions, and ELOS.

We propose changes to part 1 definitions to clarify new requirements proposed for part 23. In addition, we propose changes to part 23 in the areas of:

• Airplane categories to allow commuter category certification of multiengine turbojets;

• Flight requirements, including standards for performance, stability, stalls, and other flight characteristics;

• Structure requirements, including standards for emergency landing conditions and fatigue evaluation;

• Design and construction requirements, including standards for flutter, takeoff warning system, brakes, personnel and cargo accommodations, pressurization, and fire protection;

• Powerplant requirements, including standards for engines, powerplant controls and accessories, and powerplant fire protection;

• Equipment requirements, including general equipment standards and standards for instruments installation, electrical systems and equipment, and oxygen systems; and

• Operating limitations and information, including standards for airspeed limitations, kinds of operation, markings and placards, and airplane flight manual and approved manual material.

II. Discussion of the Proposed Regulatory Amendments

1. Part 1: Definitions Clarifying Power and Engine Terms

We propose to amend part 1 definitions for “rated takeoff power,” “rated takeoff thrust,” “turbine engine,” “turbojet engine,” and “turboprop engine.” Defining engine-specific terms would clarify the new requirements proposed for part 23. The need to define some of these terms was also shown by the following communications between the FAA and members of industry. These communications were based on the existing part 1 definitions for “rated takeoff power” and “rated takeoff thrust”, which limit the use of these

power and thrust ratings to no more than five minutes for takeoff operation.

In 1990, the Airline Transport Association (ATA) sent a letter to the FAA asking the FAA to allow 10-minute OEI takeoff approval. At some airports (mostly foreign), the climb gradient capability needed to clear distant obstacles after takeoff requires more time at takeoff thrust than 5 minutes. Using only 5 minutes of takeoff thrust to clear distant obstacles limits the maximum allowable airplane takeoff weight. The availability of takeoff thrust or power for use up to 10 minutes, granted by some foreign authorities, enabled some foreign operators to dispatch at an increased gross weight over that allowed for U.S. operators. U.S. operators asked for equal treatment in similar circumstances. The FAA has approved these requests when they have been properly substantiated. This policy would also apply to operators of part 23 turbojet-powered airplanes in order to achieve a climb gradient necessary to clear obstacles.

2. Expanding Commuter Category to Include Turbojets

Currently, we limit commuter category airplane requirements to propeller-driven, multiengine airplanes. The FAA has issued exemptions to allow turbojets weighing more than 12,500 pounds to be certificated under part 23. The proposal to change § 23.3 would codify the current FAA practice of certificating multiengine turbojets weighing up to and including 19,000 pounds under part 23 in the commuter category.

3. Performance, Flight Characteristics, and Other Design Considerations

a. Performance

We propose to extend the commuter category performance requirements to multiengine turbojets weighing more than 6,000 pounds. This proposal codifies requirements that we currently impose by special conditions for these airplanes. Amendment 23-45 (58 FR 42136) requires all turbine-powered airplanes weighing 6,000 pounds or less to meet many of the same performance standards for reciprocating-powered airplanes weighing more than 6,000 pounds. The FAA has determined that turbojets should meet a higher level of safety than reciprocating-powered airplanes in the same weight band. By requiring turbojets over 6,000 pounds to meet the higher commuter category certification requirements, the FAA would remain consistent in establishing more stringent requirements for turbojet airplanes than for reciprocating airplanes.

The ARC recommended no changes to performance requirements in §§ 23.51, 23.53, 23.55, 23.57, 23.59 and 23.61. The ARC pointed out that applying the commuter category takeoff performance requirements to multiengine turbojets weighing more than 6,000 pounds would include restrictions that could become a takeoff weight limitation for operations. The ARC stated that these requirements are too restrictive for part 91 operations. However, existing multiengine turbojets weighing more than 6,000 pounds are required to meet these standards through special conditions, and we have seen negligible operational impact. We have no rationale or basis to support a reduced level of safety for part 23 turbojets.

The ARC also reviewed FAA and Flight Safety Foundation accident studies for engine failure on takeoff. The ARC determined that existing normal category part 23 turboprops operated under part 135 have an acceptable safety record when compared to turbojets. Furthermore, turboprops in the accident studies were not certificated with any of the commuter category performance requirements for climb gradients.

The ARC believed the safety record of the turboprops had more to do with the inherent reliability of turbine engines rather than the higher climb gradient. An ARC member suggested the higher OEI climb gradients originated in part 25 during the large piston transport airplane engine era. Back then, the large piston engines were prone to failure on takeoff or initial climb, and the requirements for OEI climb gradients were necessary for safety.

The ARC further believed raising the OEI climb performance requirements for most multiengine airplanes was appropriate. However, the ARC debated the appropriate OEI climb gradients for turbine-powered airplanes over 6,000 pounds. Based on the reliability of turbine engines, the ARC only recommended raising the climb performance to 1 percent. This matched the ARC's recommendation of 1 percent for turbojets under 6,000 pounds. The ARC's recommendation, however, would reduce the OEI climb performance that is currently required through special conditions from 2 to 1 percent for turbojet-powered airplanes over 6,000 pounds.

Existing multiengine turbojets weighing more than 6,000 pounds are required through special conditions to meet the commuter category performance requirements (2 percent climb gradient) for OEI. We propose to maintain the 2 percent OEI climb gradient currently applied through special conditions for multiengine turbojets over 6,000 pounds. This climb gradient requirement is safe and prudent, and it is not reasonable to reduce the level of safety that already exists with part 23 turbojets.

Although special conditions have required 2 percent OEI climb gradient for multiengine turbojets over 6,000 pounds, there was no data to support whether small turbojets under 6,000 pounds could meet the higher 2 percent climb gradient while maintaining reasonable utility. If our rule changes to §§ 23.63 and 23.67 negatively impacted their utility (i.e., weight-carrying ability), the rule might give the piston-powered, multiengine airplanes a distinct market advantage. Accident studies show that turbojets are generally safer than piston-powered airplanes. Therefore, we wanted to compromise by proposing a requirement that would provide an adequate minimum safety standard and encourage production of more turbojets. One multiengine turbojet in this weight band has been operated as an air taxi, and the FAA expects this type of operation to grow. While this particular jet is capable of higher climb performance, we propose only to increase the OEI climb performance requirement to 1.2 percent because other jets in this weight band may not be capable of the higher 2 percent climb performance. Based on accident data, 1.2 percent provides an adequate minimum safety standard.

Historically, piston-powered, multiengine airplanes were allowed a lower climb requirement because they would not have any weight-carrying utility if forced to meet the same requirements of the larger airplanes. We are continuing this philosophy in this proposal. (
See
summary in the table below.)

Table 1—One-Engine Inoperative Climb Requirements to 400 Feet Above Ground Level (AGL)

Multiengine type/airplane weight band
Current rule

ARC
recommendation (percent)

FAA proposal (percent)

Pistons >6,000 lbs.
Measurably positive
1.0
1.0

Turboprops ≤6,000 lbs.
Measurably positive
1.0
1.0

Turboprops >6,000 lbs.
Measurably positive
1.0
1.0

Turbojets ≤6,000 lbs.
Measurably positive
1.0
1.2

Turbojets >6,000 lbs.
2.0 percent imposed through special conditions
1.0
2.0

In addition to the proposed changes in takeoff and climb performance requirements described above, we also propose changes to other performance rules. Currently, part 23 reflects the traditional small airplane definition of landing configuration stall speed (V
SO
). However, certification personnel have interpreted V
SO
in part 23 as being the same as that in part 25. This interpretation has resulted in an unnecessary burden to the applicant. We are revising the part 23 requirement so that it is distinct from the part 25 requirement and to retain the original definition of the term. We are proposing to revise paragraphs (a) and (c) of § 23.49 to clarify the section. We are also proposing to correct the title of this section in the CFR to “Stalling speed” instead of “Stalling period.”

V
SO
, by definition, is the stall speed in the maximum landing flap configuration and is not applicable to other flap configurations. (V speeds are defined in part 1. To simplify the understanding of the proposed rule, we are adding this information here.) Current § 23.73 references V
SO
. The reference to V
SO
in this paragraph is an error and should be changed to reference the stall speed for a specified flap configuration (V
S1
)
.
The reference landing approach speed (V
REF
) should be based on 1.3 times the V
S1
. We propose to amend the standards to address airplanes certificated under part 23 that may have more than one landing flap setting. We also propose to apply the commuter category requirements for V
REF
to multiengine turbojets over 6,000 pounds maximum weight. In addition, we propose to apply the commuter category requirements for balked landings in § 23.77 to all multiengine turbine-powered airplanes over 6,000 pounds, consistent with current special conditions for multiengine turbojets and turbine-powered airplanes over 6,000 pounds.

b. Flight Characteristics

The FAA proposes to define “maximum allowable speed” and to clarify the specific speed limitations, which include specific criteria for V
FC
, V
LE
, or V
FC
/M
FC
as appropriate. The proposal for § 23.177 would codify special conditions that include specific speed limitations. Furthermore, we are adding a new paragraph to § 23.175(b) to define the V
FC
/M
FC
(maximum speed for stability characteristics) term in part 23. This definition was inadvertently omitted in the last revision to part 23.

The FAA proposes to amend the combined lateral-directional dynamic stability damping requirements for airplanes that operate above 18,000 feet. The existing stability damping requirements, which apply at all certificated altitudes, were developed when small airplanes typically operated under 18,000 feet and were not equipped with yaw dampers. The existing requirement remains appropriate for low altitude operations, such as for approaches, but it is not appropriate for larger airplanes that typically use yaw dampers and fly at altitudes well above 18,000 feet. The FAA has issued exemptions for most turbojets certificated under part 23 because it is appropriate for high-altitude, high-speed operations. The proposed changes to § 23.181 would reduce the stability damping requirement at 18,000 feet and above. If adopted, this amendment would reduce the number of exemptions processed by the FAA by codifying what is allowed as an acceptable means of compliance.

The FAA proposes to amend the existing stall requirements in §§ 23.201 and 23.203 to include language from the turbojet special conditions. We propose clarifying the requirements for wings-level and accelerated turning stalls. We also propose changing the roll-off requirements for wings-level, high-altitude stalls.

The FAA proposes additional high-speed and high-altitude requirements to §§ 23.251 and 23.253 to address the new generation of high performance part 23 airplanes. The FAA also proposes to extend provisions from part 25, §§ 25.251(d) and (e), to part 23. However, we would limit the requirements to airplanes that fly over 25,000 feet and have a Mach dive speed (M
D
) faster than Mach 0.6 (M 0.6) to be consistent with part 25 requirements. The FAA also proposes the use of V
DF
/M
DF
, which is demonstrated flight dive speed (V
DF
) or Mach (M
DF
) as referenced in the part 23 turbojet special conditions.

Furthermore, we propose adding requirements in a new § 23.255 that would be based on § 25.255 and would address potential high-speed Mach effects for airplanes with M
D
greater than M 0.6. The FAA's approach would only apply the part 25-based requirements to airplanes that incorporate a trimmable horizontal stabilizer, which is consistent with the ARC's recommendation. The ARC's recommendation was based on the positive service history with the existing fleet of part 23 and part 25 turbojets designed with conventional horizontal tails that use trimmable elevators. The industry manufacturers have designed airplanes that have experienced upset incidents involving out-of-trim conditions with a trimmable horizontal stabilizer. Service experience shows that out-of-trim conditions can occur in flight for various reasons, and the control and maneuvering characteristics of the airplane may be critical in recovering from upsets. The proposed language would require exploring the airplane's high-speed control and maneuvering characteristics.

c. Other Design Considerations

We propose to revise language in § 23.703 in the introductory text and paragraph (b) to add takeoff warning system requirements to all airplanes over 6,000 pounds and all turbojets. The definition of an unsafe condition, in this case, is the inability to rotate or prevent an immediate stall after rotation. High temporary control forces that can be quickly “trimmed out” would not necessarily be considered unsafe.

We have proposed the commuter category, rejected takeoff requirements for all multiengine turbojets over 6,000 pounds. The higher takeoff speeds and distances for these airplanes make the ability to stop in a specified distance a safety issue. Additional braking considerations accompany the rejected

takeoff requirements. Therefore, we propose to apply the requirements for brakes in § 23.735 to all multiengine turbojets over 6,000 pounds, as well as to all commuter category airplanes.

4. Structural Considerations for Crashworthiness and High-Altitude Operations

The FAA proposes to codify into § 23.561 the recent turbojet special conditions that were not available during the ARC's effort. This proposal applies to single-engine turbojets with centerline engines embedded in the fuselage. Part 23 did not encompass embedded centerline engine installations, except for in-line propeller-pusher types. In light of several new turbojet designs, it is prudent to require greater engine retention strength for engines mounted aft of the cabin. This is especially true for engines mounted inside the fuselage behind the passengers. The proposed requirement would reduce the potential for the engine to separate from its mounts under forward-acting crash loads and subsequently intrude into the cabin. We recently applied this proposed requirement to a single-engine turbojet through special conditions.

The ARC did not consider emergency landing dynamic conditions in § 23.562. We recognize, however, that § 23.562 should be applicable to all turbojets, including those operating in the commuter category. All manufacturers of recently certificated commuter category turbojets have agreed to comply with § 23.562. The FAA proposes to amend § 23.562 to include all commuter category turbojets. This proposal would adopt current industry practice and ensure a consistent level of safety for all turbojets.

At one time, the FAA proposed to apply the requirements for emergency landing dynamic conditions to all commuter category airplanes.
2

Subsequently, we published new certification and operations requirements for commuter operations.
3

These actions required certain commuter operators that previously conducted operations under part 135 to conduct those operations under part 121. This rule, in effect, eliminated the use of new part 23 airplanes with 10 seats or more in scheduled service. This action negated any projected benefits supporting the addition of emergency landing dynamic conditions to commuter category airplanes.

2
58 FR 38028.

3
60 FR 65832 and 61 FR 2608.

The commuter operators affected were those conducting scheduled passenger-carrying operations in airplanes that have passenger-seating configurations of 10 to 30 seats (excluding any crewmember seat) and those conducting scheduled passenger-carrying operations in turbojet airplanes regardless of seating configuration. The action increased safety in scheduled passenger-carrying operations and clarified, updated, and consolidated the certification and operations requirements for persons who transport passengers or property by air for compensation or hire.

In terms of overall configuration, commuter category turbojets have little resemblance to their propeller-driven counterparts. During an emergency landing, most commuter category turbojets will have more structure underneath the cabin floor available to absorb energy than traditional propeller-driven airplanes. This capability, along with the differences in the overall airplane configuration of turbojets, would suggest the test conditions specified in the current rule should be applicable to all turbojets. However, commuter category airplanes cannot exceed a maximum takeoff weight of 19,000 pounds. With this limitation, the amount of crushable, energy absorbing structure is small when compared to most part 25 airplanes. For this reason, we propose to require the dynamic test conditions specified in part 23 rather than those in § 25.562.

We also propose to modify the seating head injury criteria (HIC) calculation in the proposed rule to be consistent with the HIC definition in part 25. This proposal addresses the concern that the HIC definition in part 23 would lead to a HIC calculation only for the total time of the head impact, which would not necessarily maximize HIC.

In the event of a ditching, the proposed change in § 23.807 would provide an alternative to meeting the current requirement for an emergency exit, above the waterline, on both sides of the cabin for multiengine airplanes. Proposed section 23.807 would allow the placement of a water barrier in the doorway before the door would be opened as a means to comply with the above waterline exit requirement. This barrier would be used to slow the inflow of water. The FAA has approved the use of this barrier as an alternative to the above waterline exit for several airplanes by issuing an ELOS finding.

Several new part 23 turbojet programs include approval for operations at altitudes above 40,000 feet. Additionally, the FAA has issued special conditions for operations up to 49,000 feet. We propose rule changes for structures and the cabin environment to ensure structural integrity of the airplane at higher altitudes. We also propose rule changes to prevent exposure of the occupants to cabin pressure altitudes that could cause them physiological injury or prevent the flight crew from safely flying and landing the airplane.

We propose to amend § 23.831 to add new paragraphs (c) and (d), which include standards appropriate for airplanes operating at high altitudes beyond those included in part 23. The proposed changes are intended to ensure flight deck and cabin environments do not result in the crew's mental errors or physical exhaustion that would prevent the crew from successfully completing assigned tasks for continued safe flight and landing. An applicant may demonstrate compliance with paragraph (d) of this requirement if the applicant can show that the flight deck crew's performance is not degraded.

The cabin environment must be conservatively specified such that no occupant would incur any permanent physiological harm after depressurization. The environmental and physiological performance limits used for demonstrating compliance must originate from recognized and cognizant authorities as accepted by the regulatory authority reviewing the compliance finding.

As part of the certification process, we would consider the entire flight profile of the airplane during the depressurization event. The profile would include cruise and transient conditions during descent, approach, landing, and rollout to a stop on the runway. We would not include taxiing as a compliance consideration because the airplane would be on the ground and could be evacuated, or flight deck windows and cabin doors could be opened for ventilation. The condition of the airplane from the beginning of the event to the end of the landing roll is accounted for when assessing the safe exit of an airplane.

We chose the words “* * * shall not adversely affect crew performance * * *” to mean the crew can be expected to reliably perform either their published or trained duties, or both, to complete a safe flight and landing. We have measured this in the past by a person's ability to track and perform tasks. The event should not result in expecting the crew to perform tasks beyond the procedures defined by the manufacturer or required by existing regulations. We use the phrase “No occupant shall sustain permanent physiological harm” to mean the occupants who may have required some

form of assistance, once treated, must be expected to return to their normal activities.

To show compliance to the proposed rule, the applicant should consider what would happen to the airplane and systems during depressurization. The applicant may also consider operational provisions, which provide for or mitigate the resulting environmental effects to airplane occupants. If the manufacturer provides an approved procedure(s) for depressurization, the flight deck and cabin crew may configure the airplane to moderate either temperature or humidity extremes, or both, on the flight deck and in the cabin. This configuration may include turning off non-critical electrical equipment and opening the flight deck door, or opening the flight deck window(s).

As with § 23.831, we find it necessary to amend the standards in § 23.841 to prevent exposure of the occupants to cabin pressure altitudes that could keep the flight crew from safely flying and landing the airplane or cause permanent physiological injury to the occupants. The intent of the proposed changes to § 23.841 is to provide airworthiness standards that allow subsonic, pressurized turbojets to operate at their maximum achievable altitudes—the highest altitude an applicant can choose to demonstrate the effects to several occupant related items after decompression. The applicant must show that: (1) The flight crew would remain alert and be able to fly the airplane, (2) the cabin occupants would be protected from the effects of hypoxia (
i.e.
, deprivation of adequate oxygen supply), and (3) if some occupants do not receive supplemental oxygen, they would be protected against permanent physiological harm.

Existing rules require the cabin pressure control system maintain the cabin at an altitude of not more than 15,000 feet if any probable failure or malfunction in the pressurization system occurs. Cabin pressure control systems on part 23 airplanes frequently exhibit a slight overshoot above 15,000 feet cabin altitude before stabilizing below 15,000 feet. Existing technology for cabin pressure control systems on part 23 airplanes cannot prevent this momentary overshoot, which prevents strict compliance with the rule. We have granted ELOS findings for this characteristic because physiological data shows the brief duration of the overshoot would have no significant effect on an airplane's occupants.

Special conditions issued for part 23 turbojets are similar and, for operating altitudes above 41,000 feet, equivalent to the requirements in § 25.841 adopted in Amendment 25-87 (61 FR 28684). That amendment revised § 25.841(a) to include requirements for pressurized cabins that were previously covered only in special conditions. The special conditions required consideration of specific failures. The FAA incorporated reliability, probability, and damage tolerance concepts addressing other failures and methods of analysis into part 25 after the issuance of the special conditions. Sections 23.571, 23.573, and 23.574 address damage tolerance requirements. We propose to require the use of these additional methods of analysis as part of this rulemaking.

This proposal also specifies a more performance-based criterion, such that failures cannot adversely affect crew performance nor result in permanent physiological harm to passengers.

(
Note:
There is a different standard for the crew than the passengers.)

Part 23 requires a warning of an excessive cabin altitude at 10,000 feet. Those regulations do not adequately address airfield operation above 10,000 feet. Rather than disable the cabin altitude warning to prevent nuisance warnings, we have issued ELOS findings that allow the warning altitude setting to be shifted above the maximum approved field elevation, not to exceed 15,000 feet. We propose to revise § 23.841 to incorporate language from existing ELOSs into the regulation.

Currently, we address oxygen systems for airplanes operating above 41,000 feet using special conditions derived from part 25. A large number of new turbojets and high-performance airplanes entering part 23 certification will operate at higher altitudes than previously envisioned for part 23 airplanes. We are proposing revisions to §§ 23.1443, 23.1445, and 23.1447 to establish requirements for oxygen systems. These new requirements would eliminate the need for special conditions for airplanes operating above 40,000 feet.

5. General Fire Protection and Flammability Standards for Insulation Materials

When we initially introduced powerplant fire protection provisions in part 23, we did not foresee turbojet engines embedded in the fuselage, nor in pylons on the aft fuselage, for airplanes certificated to part 23 standards. We propose to add fire protection requirements for turbojets in §§ 23.1193, 23.1195, 23.1197, 23.1199, and 23.1201. Part 23 has historically addressed fire protection through prevention, identification, and containment. Manufacturers have provided prevention through minimizing the potential for ignition of flammable fluids and vapors. Also historically, pilots had been able to see the engines and identify the fire or use the incorporated fire detection systems, or both. The ability to see the engine provided for the rapid detection of a fire, which led to a fire being rapidly extinguished. However, engine(s) embedded in the fuselage or in pylons on the aft fuselage do not allow the pilot to see a fire.

Isolating designated fire zones, through flammable fluid shutoff valves and firewalls, provides for containment of a fire. Containing fires ensures that components of the engine control system function effectively to permit a safe shutdown of the engine. We have only required a demonstration of containment for 15 minutes. If a fire occurs in a traditional part 23 airplane, the corrective action is to land as soon as possible. For a small, simple airplane originally envisioned by part 23, it is possible to descend the airplane to a suitable landing site within 15 minutes. If the isolation means do not extinguish the fire, the occupants can safely exit the airplane before the fire breaches the firewall.

Simple and traditional airplanes normally have the engine located away from critical flight control systems and the primary structure. This location has ensured that throughout the fire event, the pilot can continue safe flight and control of the airplane and predict the effects of a fire. Other design features of simple and traditional airplanes (
e.g.
, low stall speeds and short landing distances) ensure that even if an off-field landing occurs, the potential for a catastrophic outcome is minimized.

Specifically for airplanes equipped with embedded engines, the consequences of a fire in an engine embedded in the fuselage are more varied, adverse, and difficult to predict than the engine fire for a typical part 23 airplane. Engine(s) embedded in the fuselage offer minimal opportunity to actually see a fire. The ability to extinguish an engine fire becomes extremely critical due to this location. With the engine(s) embedded in the fuselage, an engine fire could affect both the airplane's fuselage and the empennage structure, which includes the pitch and yaw controls. A sustained fire could result in damage to this primary structure and loss of airplane control before a pilot could make an emergency landing. For embedded engine installations, we also propose requiring a two-shot fire-extinguishing system because the metallic components

in the fire zone can become hot enough to reignite flammable fumes after someone extinguishes the first fire.

We propose to upgrade flammability standards for thermal and acoustic insulation materials used in part 23 airplanes. The current standards do not realistically address situations where thermal or acoustic insulation materials may contribute to propagating a fire. The changes we propose are based on the requirements in § 25.856(a), which were adopted following accidents involving part 25 airplanes, such as the Swissair MD-11. We believe the proposed standards would enhance safety by reducing the incidence and severity of cabin fires, particularly those in inaccessible areas where thermal and acoustic insulation materials are installed.

The proposed standards include new flammability tests and criteria that address flame propagation, which would apply to thermal/acoustic insulation material installed in the fuselage of part 23 airplanes. Certification tests would consist of samples of thermal/acoustic insulation that would be exposed to a radiant heat source and a propane burner flame for 15 seconds. The insulation must not propagate flame more than 2 inches away from the burner. The flame time after removal of the burner must not exceed 3 seconds on any specimen. (
See
proposed Part II, Appendix F to part 23 for more details.)

Current flammability requirements focus almost exclusively on materials located in occupied compartments (§ 23.853) and cargo compartments (§ 23.855). The potential for an in-flight fire is not limited to those specific compartments. Thermal/acoustic insulation can be installed throughout the fuselage in other areas, such as electrical/electronic compartments or surrounding air ducts, where the potential also exists for materials to spread fire. Proposed § 23.856 accounts for insulation installed within a specific compartment in areas the regulations might not otherwise cover. Proposed § 23.856 would be applicable to all part 23 airplanes, regardless of size or passenger capacity. Advisory material describing test sample configurations to address design details (
e.g.
, tapes and hook-and-loop fasteners) is available in DOT/FAA/AR-00/12, Aircraft Materials Fire Test Handbook, dated April 2000. A copy of the handbook has been placed in the docket for this rulemaking.

Insulation is usually constructed in what is commonly referred to as a “blanket.” Insulation blankets typically consist of two things: (1) A batting of a material generically referred to as fiberglass (
i.e.
, glass fiber or glass wool), and (2) a film covering to contain the batting and to resist moisture penetration, usually metalized or non-metalized polyethylene terephthalate (PET), or metalized polyvinyl fluoride (PVF). Polyimide, a heat-resistant fiber used in insulation and adhesive, is another film used on certain airplanes. Regardless of the film type used, there are variations associated with its assembly for manufacture that result in performance differences from a fire safety standpoint. These variations include the density of the film, the type and fineness of the scrim bonded to the film, and the adhesive used to bond the scrim to the film. The scrim resembles a screen, and the mesh can vary in fineness. The scrim is usually constructed of either nylon or polyester and is bonded to the backside of the film to add shape and strength to the surface area. The adhesive used to bond the scrim to the film also varies. However, the type of adhesive used is important because fire retardant is frequently concentrated in the adhesive of the assembled sheet.

6. Powerplant and Operational Considerations

Current § 23.777 standardizes the height and location of powerplant controls because pilots may become confused and use the wrong controls on propeller-driven airplanes. This requirement, however, does not include single-power levers (which are typical for electronically-controlled engines). The FAA currently makes an ELOS finding for each airplane program that includes a single-power lever. We propose to revise paragraph (d) in § 23.777 to incorporate the ELOS language.

We propose to revise § 23.903, paragraph (b)(2), to add requirements for fuselage-embedded, turbofan engine installations. These types of engine installations may have a negative impact on passenger safety because passengers occupy an area directly ahead of the turbojet engine fan disk. Certain turbofan engine designs have failure conditions that allow the fan disk to exit the front of the engine. This failure condition occurs if engines have bearing/shaft configurations that would allow the disk to separate from the engine and travel forward. If the engine has demonstrated this failure mode or if an analysis shows such a failure is conceivable, then the requirements of this section would apply. This requirement would be applicable to engines embedded in the airplane's fuselage where it could move forward into areas occupied by passengers or crew when a disk fails.

In addition to the changes described above, we also propose requiring that electronic engine control systems meet the equipment, systems, and installation standards of § 23.1309. We have applied this requirement to all digital engine controls in part 23 airplanes by special condition. The proposed rule change for § 23.1141 would largely eliminate the need to issue special conditions on future certification programs.

The ARC believed few single-engine airplane manufacturers have analyzed the criticality of their control system to meet the requirements of this proposed rule. The fundamental rule change recommended by the ARC for § 23.1141 was not intended to invalidate or overrule the 14 CFR part 33 certification requirements. The proposed change for § 23.1141 is intended for consideration of the airframe/engine interface and how that interface protects against high intensity radiated fields (HIRF) and lightning.

Over the years, airplane engines, including turbines, generated their own ignition system electrical power separate from the airplane's electrical generation system. Even with a complete electrical failure of the primary electrical systems, the engines would still run and be fully functional. However, all new engines are not designed with self-electrical-generation capability. Some new engines rely on the airplane's electrical system to continue running and to be fully functional. Revising § 23.1165(f) would ensure that when approved engines are installed on part 23 airframes, the engine ignition system is identified as an essential load. This would ensure that those engines have power during emergencies.
4

4
Under the proposed changes, we would certificate new engines, which include electronic ignition systems and engines with electronic controls necessary for the engine's operation, through the Engine and Propeller Directorate.

7. Avionics, Systems, and Equipment Changes

Updated system requirements should reduce the regulatory burden on the applicant by clarifying and expanding the applicability of §§ 23.1301 and 23.1309 to specific systems and functions. Most new part 23 airplane manufacturers are installing electronic primary flight displays (PFD) and multifunction displays (MFD) that replace conventional electromechanical and mechanical instruments. These new systems also offer more capability, reliability, and features that improve safety.

We propose changes that would address displays, software, hardware, and power requirements. Besides advanced avionics and integrated systems, we propose to update the certification requirements to consider other advanced technologies (
e.g.
, digital engine controls). We intend to apply lessons learned from recent small turbojet certification programs to update requirements for intended function and system safety.

The ARC did not make a specific recommendation for § 23.1301. However, the FAA seeks to clarify the intent of this section because it is frequently misinterpreted and misapplied. Clarifying the intent of § 23.1301 would improve standardization for systems and equipment certification, particularly for non-required equipment and non-essential functions embedded within complex avionic systems. Our intent is for the applicant to define proper functionality and to propose a means of compliance acceptable to the Administrator. We expect applicants to coordinate or negotiate deviations from established means of compliance with the Administrator as early as possible to minimize delay to project schedules.

We propose to remove § 23.1301(d), which currently states that equipment must “function properly when installed.” The proposed change would limit the scope of the rule since it would apply only to equipment required for type certification or operation. We propose a related change to clarify similar language in § 23.1309 for proper functionality of installed equipment.

The ARC did not make a specific recommendation for § 23.1303. However, the FAA seeks to clarify the intent of this rule to accommodate new technology and eliminate the need to issue an ELOS for part 23 airplanes. We propose to amend § 23.1303(c) by changing the current requirement from “A direction indicator (non-stabilized magnetic compass)” to “A magnetic direction indicator.” Section 23.1303 does not include a direction indicator, other than the typical non-stabilized compass for part 23 airplanes. As new technology becomes more affordable for part 23 airplanes, many electronic flight instrument systems will use magnetically stabilized direction indicators (or electric compass systems) to measure and indicate the airplane heading to provide better performance.

Current regulations require powerplant displays, referred to as “indicators” in § 23.1305, to provide trend or rate-of-change information. Advisory Circular (AC) 23.1311-1B, Installation of Electronic Displays in Part 23 Airplanes, dated June 14, 2005, currently provides a basis for an ELOS finding for digital engine display parameters.
5

The proposed rule changes to §§ 23.1303, 23.1305, and 23.1311 would largely eliminate the need to issue ELOS findings for these systems and help standardize certification of new technology.

5
A copy of the advisory circular is available on the Internet at
http://www.faa.gov/regulations_policies/.

The ARC also did not make a specific recommendation for § 23.1307. However, the FAA seeks to clarify language so applicants understand they may need additional equipment to operate their airplane. Part 23 is a minimum performance standard, and it may not include all the required equipment for commercial operations under 14 CFR part 135. We propose to include parts 91 and 135 operations as examples to use when deciding which equipment is necessary for an airplane to operate at the maximum altitude.

a. System SafetyAssessment Requirements

We originally designed the system safety assessment requirements of § 23.1309 to address certification of electronic systems driven by microprocessors and other complex systems. However, the requirements of § 23.1309 are being applied to conventional mechanical and electromechanical systems with well-established design and certification processes. This was not our intent, and we propose to revise § 23.1309 to clarify the intended application of the rule.

Proposed changes for § 23.1309 also clarify the intent for certification of electronic engine controls. The current section excludes systems certificated with the engine. Therefore, we use special conditions for all electronic engine control installation approvals to capture the evaluation requirements of § 23.1309. We applied special conditions to the interface of the electronic engine control system and the airplane. We also applied special conditions to verify that the installation does not invalidate the assumptions made during part 33 certification of the engine. This proposal would address electronic engine controls and eliminate the need for special conditions to apply § 23.1309 to electronic engine control systems.

Proposed § 23.1309(a) would have requirements for two different types of equipment and systems installed in the airplane. Proposed § 23.1309(a)(1) would cover the equipment and systems that have no negative safety effect and those installed to meet a regulatory requirement. Such systems and equipment are required to “perform as intended under the airplane operating and environmental conditions.” Proposed § 23.1309(a)(2) would require the applicant to show that all equipment and systems (including approved “amenities,” such as a coffee pot and entertainment systems) have no safety effect on the operation of the airplane. The phrase “improper functioning” identifies equipment and system failures that have a potentially negative effect on airplane safety. Therefore, we must consider their potential failure condition(s). Using § 23.1309, we must analyze any installed equipment or system that has potential failure condition(s) that are catastrophic, hazardous, major, or minor to determine their impact on the safe operation of the airplane.

We propose to clarify the certification requirements, environmental qualification test requirements, and our intent for determining proper “intended function” of non-required systems and equipment that do not have a safety effect on the airplane. A problem with the current requirements for airplane manufacturers arises when certification authorities question installation of non-required systems and equipment that do not perform following their specifications and, therefore, are “not functioning properly when installed.” Usually, normal installation practices can be based on a relatively simple qualitative installation evaluation. If the possible safety impacts (including failure modes or effects) are questionable, or isolation between systems is provided by complex means, more formal structured evaluation methods or a design change may be necessary. We do not require these types of equipment and systems to function properly when installed. However, we would require them to function when they are tested to verify that they do not interfere with the operation of other airplane equipment and systems and do not pose a hazard in and of themselves.

Also under proposed changes to § 23.1309(a), we would replace the conditional qualifiers of “under any foreseeable operating condition,” contained in the current § 23.1309(b)(1), with “under the airplane operating and environmental conditions.” Our intent with this proposal is for the applicant to take two actions. First, the applicant must consider the full normal operating envelope of the airplane, as defined by the airplane flight manual (AFM), with any modification to that envelope associated with abnormal or emergency procedures and any anticipated crew

action. Second, the applicant must consider the anticipated external and internal airplane environmental conditions, as well as any additional conditions where equipment and systems are assumed to “perform as intended.” We propose to make this change in response to an observation that although certain operating conditions are foreseeable, achieving normal performance when they exist is not always possible (
e.g.
, you may foresee ash clouds from volcanic eruptions, but airplanes with current technology cannot safely fly in such clouds).

The FAA currently accepts equipment that is susceptible to failures if these failures do not contribute significantly to the existing risks (
e.g.
, some degradation in functionality and capability is routinely allowed during some environmental qualifications, such as HIRF and lightning testing). System lightning protection specifically allows the loss of function and capability of some electrical/electronic systems when the airplane is exposed to lightning, if “these functions can be recovered in a timely manner.”

Proposed § 23.1309(a)(3) is applicable for all functional reliability, flight testing, or flight evaluations. This proposed change clarifies the FAA's expectations for functional testing during certification of complex systems, but it is not meant to increase the testing burden on the applicant. The FAA's intent is to prohibit certification of systems with known defects in required functions that could impact safety. For example, it would not be acceptable for an integrated avionics system to be approved until known functional defects in required functions are corrected. The system would not be allowed to exhibit unintended or improper functionality for flight critical functions. The rate of occurrence of failures, malfunctions, and design errors must be appropriate for the failure condition(s) of the type of system and airplane.

Proposed § 23.1309(b) would codify a long-established means of compliance with current § 23.1309(b) and update failure condition(s) terminology used in related system safety assessment documents developed by industry working groups (
e.g.
, RTCA and the Society of Automotive Engineers (SAE)). This means of compliance identifies four classes of airplanes as defined in Appendix K of this proposal and applies appropriate probability values and development assurance levels for each class. The original text of § 23.1309(b)(4) has been retained and appears as § 23.1309(b)(5) in this revision. The proposed changes to § 23.1309(c) and (d) are meant to define the proper scope and intent for applying § 23.1309 depth of analysis for system safety assessments to all systems.

With proposed § 23.1309(f), we would make § 23.1309 compatible with the current § 23.1322 (“Warning, caution, and advisory lights”) that distinguishes between caution, warning, and advisory lights installed on the flight deck. Rather than only providing a warning to the flight crew, which is required by the current rule, proposed § 23.1309(f) would require that information concerning an unsafe system operating condition(s) be provided to the flight crew.

A warning indication would still be required if immediate action by a flight crewmember were required. The particular method of indication would depend on the urgency and need for flight crew awareness or action that is necessary for the particular failure. Inherent airplane characteristics may be used in lieu of dedicated indications and annunciations that can be shown to be timely and effective. The use of periodic maintenance or flight crew checks to detect significant latent failures when they occur should not be used in lieu of practical and reliable failure monitoring and indications.

Proposed § 23.1309(f) would clarify the current rule by specifying that the design of systems and controls, including indications and annunciations, must reduce crew errors that could create more hazards. The additional hazards to be minimized would be those that are caused by inappropriate actions made by a crewmember in response to the failure, or those that could occur after a failure. Any procedures for the flight crew to follow after the occurrence of a failure indication or annunciation would be described in the approved Airplane Flight Manual (AFM), AFM revision, or AFM supplement, unless they are accepted as part of normal aviation abilities.

Current § 23.1309 (c) and (d) are not directly related to the other safety and analysis requirements of § 23.1309. The ARC considered it appropriate to state the requirements separately for clarity. We agree with this suggested change and propose to add a new § 23.1310 to accommodate the change. The requirements as originally stated in current § 23.1309 would not change, except for a new section number.

We propose several changes to § 23.1311(a)(5) for plain language purposes. In proposed § 23.1311(a)(5), we replace the phrase “individual electronic display indicators” with “electronic display parameters.” The term “indicator” has a long-standing definition based on conventional, mechanical indicators; therefore, the term has caused confusion. These electronic display parameters could be integrated on one electronic display that is independent of the primary flight display. In proposed § 23.1311(a)(6), we add the phrase “that provide a quick-glance sense of rate and, when appropriate, trend information” to clarify “sensory cues.”

We propose to add the term “when appropriate” to eliminate the requirement to display trend information when it would otherwise provide intuitive information to the pilot. For example, the trend for fuel burn is always negative. We propose to remove the remainder of section (a)(6), “* * * that are equivalent to those in the instrument being replaced by the electronic display indicator” to prevent confusion since most instruments will be electronic. In proposed § 23.1311(a)(7), we have added the word “equivalent” to make acceptable instrument markings on electronic displays that are equivalent to those instrument markings on conventional mechanical and electromechanical instruments.

In proposed § 23.1311(b), we replace the phrase “remain available to the crew, without need for immediate action” with “be available within one second to the crew with a single pilot action or by automatic means.” The proposed language allows an applicant to take credit for reversionary or secondary flight displays on a multi-function flight display (MFD) that provides a secondary means of primary flight information (PFI). This is acceptable if the display can “be available within one second to the crew with a single pilot action or by automatic means.” MFD's may also display PFI as needed to ensure continuity of operations. The display of PFI on reversionary (secondary) displays must be arranged in the basic T-configuration. Also, such displays must be legible and usable from the pilot's position with minimal head movement to meet the requirements of § 23.1321.

There are three acceptable methods for meeting the requirements of § 23.1311(b)—(1) Dedicated standby instruments, (2) dual primary flight displays (PFDs), or (3) reversionary displays that display independent attitude. The standby instruments, or another independent PFD, would ensure that primary flight information is available to the pilot during all phases of flight and system failures. The

electronic display systems with dual PFDs should incorporate dual, independently-powered sensors that would provide primary flight parameters (
e.g.
, attitude heading reference system (AHRS) with comparators and dual air data computer (ADC)). A reversionary configuration would have a single pilot action that would force MFD displays into reversionary mode operation by a single pilot action within one second or less. However, the PFI must be displayed in substantially the same format and size in the reversionary mode as it is in normal mode. The single pilot action should be easily recognized, readily accessible, and have the control within the pilot's primary field of view.

The reversionary method could include an automatic reversionary display with a single pilot action. If PFI on another display is not provided, we would require automatic switching to ensure PFI is available to the pilot. This automatic reversionary capability would cover most possible malfunctions. While a total loss of the display may not be reliably detected automatically, such a failure condition would be obvious to the pilot. Malfunctions that result in automatic switching would be extensive enough to ensure PFI is available at the reliability level required by § 23.1309. If such a malfunction occurs, a single pilot action would provide a full display of the essential information on the remaining display within one second. All modes, sources, frequencies, and flight plan data would be exactly as they were on the PFD before the failure.

Another reversionary method would include a means to access the reversionary mode manually through a single pilot action. Manual activation of the reversionary mode on the MFD through single action by the pilot would be acceptable when procedures to activate the PFI are accomplished before entering critical phases of flight. The PFI would display continuously on the reversionary display during critical phases of flight (
e.g.
, takeoff, landing, and missed or final approach).

To meet the proposed turbojet performance requirements in subpart B, the pilot would need accurate speed indicators while accelerating on the runway. We propose to revise § 23.1323(e) to add the requirement to calibrate the airspeed system down to 0.8 of the minimum value of V
1
. Also, we propose to adopt the language used in part 25 for this same requirement because it is more in line with operating new part 23 turbojets.

The proposed changes to § 23.1331 would apply to instruments that rely on a power source to provide required flight information for instrument flight rules (IFR) operations. Consequently, this section would apply to all flight instruments, such as those required by parts 23, 91, 121, and 135. Airplanes limited by type design to visual flight rules (VFR) operations would not have to comply with the requirements of proposed § 23.1331(c).

Each independent power source must provide sufficient power for normal operations throughout the approved flight envelope of the airplane and for any operations approved for the airplane. Section 23.1331(c) would not require the installation of dual alternators or vacuum systems on single-engine airplanes. One option would include a dedicated battery that meets the requirements of § 23.1353(h) for electrical instrument loads essential to continued safe flight and landing. Another option would include separately powered instruments for primary and standby use. The last option would include performing a system safety analysis, per § 23.1309, to identify the procedures necessary to verify the charge state of any airplane starting battery that is used to power a stand-by system.

The ARC did not make a specific recommendation for § 23.1353. However, we propose to add additional battery endurance requirements depending on the airplane's altitude performance. Proposed § 23.1353 addresses the power needs of new all-electrical instruments, navigation and communications equipment, and engine controls.

When § 23.1353(h) was adopted, part 23 airplanes were mostly mechanical. We did not envision all-electric, or almost all-electric, airplanes. Current § 23.1353(h) requires 30 minutes of sufficient electrical power for a reduced or emergency group of equipment and instrumentation. We considered 30 minutes adequate to reach VFR conditions to continue flying to an adequate airport and to accomplish a safe landing for traditional part 23 airplanes. We did not envision integrated electric cockpits when we developed § 23.1353(h). New part 23 airplanes are being certificated with all-electrical instruments, including the standby instruments. This reliance on electric power increases the importance of ensuring adequate battery power until the pilot can descend and make a safe landing.

Most new engines utilize electronic engine controls. These engine controls may rely on the airplane's electrical system for power and to control fuel and ignition. Large engines typically installed on part 25 airplanes have a dedicated power source running off the engine; as long as the engine is running, the electronic engine control has power. Some of the smaller, simpler engines emerging in part 23 airplanes may not have these dedicated power sources and may rely on the airplane's electrical system to keep functioning.

We believe that most new turbine-powered airplanes, and some turbocharged, piston-powered airplanes, will operate at high altitudes under IFR. Under these conditions, 30 minutes may not be adequate for battery power because of the time it would take to descend from maximum altitude to find visual meteorological conditions (VMC) and land, or to perform an instrument approach for a landing. For these reasons, proposed § 23.1353(h) would extend the battery time requirement to 60 minutes for airplanes approved with a maximum altitude above 25,000 feet.

Many new single-engine airplanes are intended for use in part 135 passenger service. Proposed § 23.1353(h) provides consistency with the operating requirements for single-engine IFR in § 135.163(i). That section requires a 60-minute battery to power all emergency equipment, as specified by the manufacturer, to allow continued safe flight and landing.

b. Allowable Qualitative Failure Condition Probabilities

We propose to add Appendix K to show the appropriate airplane systems probability standards, failure conditions, and related development assurance for four certification classes of airplanes designed to part 23 standards. Proposed Appendix K includes development assurance levels that correlate to the software levels in RTCA/DO-178B and the complex design assurance levels in RTCA/DO-254. We provided quantitative values in Appendix K to indicate the order of probability range for each certification class and failure condition.

As used in § 23.1309, the FAA proposes the following definitions for terms used in Appendix K:

i.
Extremely remote failure conditions:
Those failure conditions not anticipated to occur to each airplane during its total life but which may occur a few times when considering the total operational life of all airplanes of this type. For quantitative assessments, refer to the probability values shown for hazardous failure conditions in Appendix K.

ii.
Extremely improbable failure conditions:
For commuter category airplanes, those failure conditions so unlikely that they are not anticipated to occur during the entire operational life of all airplanes of one type. For other

classes of airplanes, the likelihood of occurrence may be greater. For quantitative assessments, refer to the probability values shown for catastrophic failure conditions in Appendix K.

iii.
Probable failure conditions:
Those failure conditions anticipated to occur one or more times during the entire operational life of each airplane. These failure conditions may be determined on the basis of past service experience with similar components in comparable airplane applications. For quantitative assessments, refer to the probability values shown for minor failure conditions in Appendix K.

iv.
Remote failure conditions:
Those failure conditions that are unlikely to occur to each airplane during its total life but that may occur several times when considering the total operational life of a number of airplanes of this type. For quantitative assessments, refer to the probability values shown for major failure conditions in Appendix K.

v.
Design appraisal:
A qualitative appraisal of the integrity and safety of the system design. An effective appraisal requires experienced judgment.

vi.
Development assurance level:
All planned and systematic actions used to substantiate, to an adequate level of confidence, that errors in requirements, design, and implementation have been identified and corrected such that the system satisfies the applicable certification basis. (The development assurance levels in Appendix K are intended to correlate to software levels in RTCA/DO-178B and complex hardware design assurance levels in RTCA/DO-254 for the system or item.)

vii.
Simple and conventional systems:
A system is considered “simple” or “conventional” if its function, the technological means to implement its function, and its intended usage are all the same as, or closely similar to, that of previously approved systems commonly used. The systems that have established an adequate service history and the means of compliance for approval are generally accepted as “simple” or “conventional.” Simple systems do not contain software or complex hardware requiring compliance by documents. These documents are the developmental assurance levels assigned in RTCA/DO-178A/B, Software Considerations in Airborne Systems and Equipment Certification, or RTCA/DO-254, Design Assurance Guidance for Airborne Electronic Hardware documents or later versions.

For simple and conventional installations, it may be possible to assess a hazardous or catastrophic failure condition(s) as being extremely remote or extremely improbable, respectively, based on an FAA approved qualitative analysis. The basis for the assessment would be the degree of redundancy, the established independence and isolation of the channels, and the reliability record of the technology involved. Satisfactory service experience on similar systems commonly used in many airplanes may be sufficient when a close similarity is established regarding both the system design and operating conditions.

viii.
Installation appraisal:
A qualitative appraisal of the integrity and safety of the installation. Any deviations from normal industry-accepted installation practices should be evaluated.

8.
Placards, Speeds, Operating Limitations, and Information

Currently, § 23.853(d)(2) requires placards for commuter category airplanes to have red letters at least
1/2
inch high on a white background at least 1 inch high. The letter size is not a requirement for the part 23 normal category or for the part 25 transport category airplanes. We propose removing the letter size requirement from this section. We also propose removing the ashtray requirement from this section since smoking is no longer allowed in parts 121 and 135 operations. We propose to amend paragraph (d)(2) of this section to read “Lavatories must have `No Smoking' or `No Smoking in Lavatory' placards located conspicuously on each side of the entry door.”

Proposed § 23.629 would allow the use of V
DF
in place of V
D
for flight testing turbojets. In addition, the proposed amendment for § 23.1505 would require airspeed limits based on a combination of analytical (V
D
/M
D
) and demonstrated (V
DF
/M
DF
) dive speeds for turbojets. Proposed § 23.1505(c) would include specific turbojet speed designations.

The ARC did not make a specific recommendation regarding § 23.1525. However, we propose to clarify language so applicants understand that additional equipment may be needed to operate their airplane. Part 23 is a minimum performance standard, and it may not include all the required equipment for operations under part 135. We propose to include parts 91 and 135 operations as examples of the kinds of operation authorized.

Proposed § 23.1545 limits the white flap arc to reciprocating engine airplanes. This change reflects standard practice for turbojets and is included in all part 23 turbojet special conditions.

Proposed § 23.1555(d)(3) would require fuel systems with a calibrated fuel quantity indication system to comply with § 23.1337(b)(1) while removing current placard requirements. Most modern turbine-powered airplanes have a calibrated fuel quantity indicating system that is density compensated and accurately indicates the actual usable fuel quantity in each tank. When using these types of fuel indicating systems, we consider the placards required by §§ 23.1555(d)(1) and (2) redundant. The placards or markings required by §§ 23.1555(d)(1) and (2) indicate the maximum capacity of the tank. For these reasons, we propose to remove the placard requirement for these accurate fuel quantity indicating systems.

The placard requirements of §§ 23.1559, 23.1563 and 23.1567 have been a source of confusion to both FAA and industry personnel relative to placard lighting. We are proposing changes to these three rules to clarify the intent of these requirements. The requirements specified on the placard in § 23.1559 are relative to preflight planning, and this placard is not normally referenced in flight. As long as the placard is “in clear view of the pilot” and the pilot can view it at night using a flashlight or other means, the intent of the rule is met. The requirement has been confusing for certification offices and this proposal makes the placard lighting intent clear. We propose to add a new paragraph § 23.1559(d), which states “The placard required by this section need not be lighted.”

With modern flight display equipment, the necessary information may now be available on that equipment and is automatically illuminated as part of the display. Therefore, we also propose to update § 23.1563 to clarify requirements for night lighting of the placard. Maneuvering speed is applicable to operations that may involve intentional large control input and is therefore not applicable to normal night operations. Most modern airplanes have means for the landing gear speed to be displayed in the airspeed indicator or on lighted portions of the landing gear control. They have the means for the airspeed indicator to display low speed awareness or other airspeed reference information to provide safety above V
MC
. Lighting this placard is unnecessary for safety and provides another source of unwanted lighting reflections in the cockpit.

The requirements specified in § 23.1567 for the limitation placard relate to acrobatic maneuvers and spin information related to preflight

planning. Since these maneuvers are not normally conducted during night operations, the placard information is not required for night flight. If the placard is “in clear view of the pilot” and the pilot can view the placard at night using a flashlight or other means, it meets the intent of the rule. The proposed change to § 23.1567 clarifies our intent of this rule relative to lighting.

We propose to incorporate the existing special conditions into the AFM requirements in §§ 23.1583, 23.1585, and 23.1587. These are necessary to be consistent with the performance requirements proposed in subpart B. These requirements include the ARC recommended, single-engine climb performance increase for turboprops.

III. Regulatory Notices and Analyses

Paperwork Reduction Act

According to the 1995 amendments to the Paperwork Reduction Act (5 CFR 1320.8(b)(2)(vi)), an agency may not collect or sponsor the collection of information, nor may it impose an information collection requirement unless it displays a currently valid OMB control number. The OMB control number for this information collection will be published in the
Federal Register,
after the Office of Management and Budget approval.

International Compatibility

In keeping with U.S. obligations under the Convention on International Civil Aviation, it is FAA policy to comply with International Civil Aviation Organization (ICAO) Standards and Recommended Practices to the maximum extent practicable. The FAA has reviewed the corresponding ICAO Standards and Recommended Practices and has identified no differences with these proposed regulations.

Regulatory Evaluation, Regulatory Flexibility Determination, International Trade Impact Assessment, and Unfunded Mandates Assessment

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 (Pub. L. 96-354) requires agencies to analyze the economic impact of regulatory changes on small entities. Third, the Trade Agreements Act (Pub. L. 96-39) prohibits agencies from setting standards that create unnecessary obstacles to the foreign commerce of the United States. In developing U.S. standards, this Trade Act requires agencies to consider international standards and, where appropriate, that they be the basis of U.S. standards. Fourth, the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4) requires agencies to prepare a written assessment of the costs, benefits, and other effects of proposed or final rules that include a Federal mandate likely to result in the expenditure by State, local, or tribal governments, in the aggregate, or by the private sector, of $100 million or more annually (adjusted for inflation with base year of 1995). This portion of the preamble summarizes the FAA's analysis of the economic impacts of this proposed rule. We suggest readers seeking greater detail read the full regulatory evaluation, a copy of which we have placed in the docket for this rulemaking.

In conducting these analyses, FAA has determined that this proposed rule: (1) Has benefits that justify its costs, (2) is not an economically “significant regulatory action” as defined in section 3(f) of Executive Order 12866, (3) the Office of Management and Budget has determined this proposal is “significant”; (4) would not have a significant economic impact on a substantial number of small entities; (5) would not create unnecessary obstacles to the foreign commerce of the United States; and (6) would not impose an unfunded mandate on state, local, or tribal governments, or on the private sector by exceeding the threshold identified above. These analyses are summarized below.

Total Benefits and Costs of This Rule

The estimated base case cost of this proposed rule is about $472,000 ($443,000 in 7 percent present value terms). The estimated safety benefits would be to avoid 14 accidents and are valued at about $82.7 million. The estimated base case efficiency benefits to streamline the part 23 certification process are valued at about $1.6 million. The total base case benefit is equal to the sum of the safety and efficiency benefits and is valued at about $84.2 million.

Who Is Potentially Affected by This Rule

This proposed rulemaking will affect manufacturers and operators of part 23 reciprocal engine, turboprop and turbojet airplanes.

Assumptions

The proposed rule makes the following assumptions:

1. The base year is 2008.

2. The average retirement age of a U.S. operated part 23 airplane is 32 years.

3. The average part 23 airplane production life cycle is 24 years.

4. The analysis period extends for 56 (32 + 24) years.

5. U.S companies would manufacture 75 percent of the turbojets forecasted by the FAA.

6. All business and commercial part 23 airplanes would operate in commuter service.

7. The value of a fatality avoided is $5.8 million.

Benefits of This Rule

For part 23 airplanes, we estimated that the proposed changes would avoid about 14 accidents over the 24-year operating lives of 37,657 new-production airplanes. The resulting benefits include averted fatalities and injuries, loss of airplanes, investigation cost, and collateral damages for the accidents. The safety benefits for averting the 14 accidents are about $82.7 million ($17.8 million in 7 percent present value terms).

Other benefits of this proposal include FAA and industry paperwork and certification time saved by standardizing and streamlining the certification of part 23 airplanes. The base case efficiency benefits for standardizing and streamlining the certification process is valued at $1.6 million.

The total base case benefit is equal to the sum of the safety and efficiency benefits and is about $84.2 million ($19.3 million in 7 percent present value terms).

Costs of This Rule

Constant-dollar (2008$) unit costs per aircraft by 14 CFR Part 23 could be as high as: $165 for turboprop airplanes and $6,550 for turbojet airplanes. Total incremental costs equal the constant-dollar unit costs multiplied by the number of aircraft produced over 10 years. The base case costs of this rule are about $472,000 ($443,000 in 7 percent present value terms) and the high case costs of this rule are about $11.1 million ($5.0 million in 7 percent present value terms).

Alternatives Considered

Alternative 1
—The FAA would continue to issue special exemptions, exceptions and equivalent levels of safety to certificate part 23 airplanes. As that would perpetuate “rulemaking by exemption,” we choose not to continue with the status quo.

Alternative 2
—The FAA continue to enforce the current regulations that affect single engine climb performance.

The FAA rejected this alternative because the accident rate on twin piston engine and turboprop airplanes identified a safety issue that had to be addressed.

Regulatory Flexibility Determination

The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA) establishes “as a principle of regulatory issuance that agencies shall endeavor, consistent with the objectives of the rule and of applicable statutes, to fit regulatory and informational requirements to the scale of the businesses, organizations, and governmental jurisdictions subject to regulation. To achieve this principle, agencies are required to solicit and consider flexible regulatory proposals and to explain the rationale for their actions to assure that such proposals are given serious consideration.” The RFA covers a wide-range of small entities, including small businesses, not-for-profit organizations, and small governmental jurisdictions.

Agencies must perform a review to determine whether a rule will have a significant economic impact on a substantial number of small entities. If the agency determines that it will, the agency must prepare a regulatory flexibility analysis as described in the RFA. However, if an agency determines that a rule is not expected to have a significant economic impact on a substantial number of small entities, section 605(b) of the RFA provides that the head of the agency may so certify and a regulatory flexibility analysis is not required. The certification must include a statement providing the factual basis for this determination, and the reasoning should be clear.

The FAA believes that this proposed rule would not have a significant impact on a substantial number of entities. The purpose of this analysis is to provide the reasoning underlying the FAA determination.

First, we will discuss the reasons why the FAA is considering this action. We will follow with a discussion of the objective of, and legal basis for, the proposed rule. Next we explain there are no relevant federal rules which may overlap, duplicate, or conflict with the proposed rule. Lastly, we will describe and provide an estimate of the number of small entities affected by the proposed rule and why the FAA believes this proposed rule would not result in a significant economic impact on a substantial number of small entities.

We now discuss the reasons why the FAA is considering this action.

The FAA proposes this action to amend safety and applicability standards of the part 23 turbojet industry to reflect the current needs of the industry, accommodate future trends, address emerging technologies, and provide for future aircraft operations. This proposal primarily standardizes and streamlines the certification of part 23 turbojet airplanes. The intent of the proposed changes to parts 1 and 23 are necessary to eliminate the current workload of exemptions, special conditions, and equivalent levels of safety determinations necessary to certificate part 23 turbojets. These proposed part 23 changes will also clarify areas of frequent non-standardization and misinterpretation and provide appropriate safety and applicability standards that reflect the current state of the industry, emerging technologies and new types of operations for all part 23 airplanes; including turbojet, turboprop and reciprocating engine airplanes.

The FAA currently issues type certificates (TCs) for part 23 turbojets using extensive special conditions. Issuance of TCs has not been significant until now because there were few part 23 turbojet programs. However, in the past five years, the number of new turbojet certification programs in part 23 has increased more than 100 percent over the past three decades.

The need to incorporate these special conditions into part 23 stems from both the existing number of new jet programs and the expected future jet programs. Codifying these special conditions will allow manufacturers to know the requirements during their design phase instead of designing the turbojet and then having to apply for special conditions that may ultimately require a redesign. Codifying will also reduce the manufacturers and FAA's paper process required to TC an airplane and reduces the potential for program delays. These proposed changes would also clarify areas of frequent non-standardization and misinterpretation, particularly for electronic equipment and system certification.

The revisions include general definitions, error correction, and specific requirements for performance and handling characteristics to ensure safe operation of part 23 transport category airplanes. The proposed revisions would apply to all future new part 23 turbojet, turboprop and reciprocating engine airplane certifications.

We now discuss the legal basis for, and objective of, the proposed rule. Next, we discuss if there are relevant federal rules, which may overlap, duplicate, or conflict with the proposed rule.

The FAA's authority to issue rules on aviation safety is found in Title 49 of the United States Code. Subtitle I, Section 106 describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the agency's authority.

This rulemaking is promulgated under the authority described in Subtitle VII, Part A, Subpart III, Section 44701. Under that section, the FAA is charged with promoting safe flight of civil aircraft in air commerce by prescribing minimum standards required in the interest of safety for the design and performance of aircraft. This regulation is within the scope of that authority because it prescribes new safety standards for the design of part 23 normal, utility, acrobatic, and commuter category airplanes.

Accordingly, this proposed rule will amend Title 14 of the Code of Federal Regulations to address deficiencies in current regulations regarding the certification of part 23 light jets, turboprops and reciprocating engine airplanes. The proposed rule would clarify areas of frequent non-standardization and misinterpretation and codify certification requirements that currently exist in special conditions.

The FAA is unaware the proposed rule will overlap, duplicate, or conflict with existing Federal Rules.

We now discuss our methodology to determine the number of small entities for which the proposed rule will apply.

Under the RFA, the FAA must determine whether a proposed rule significantly affects a substantial number of small entities. This determination is typically based on small entity size and cost thresholds that vary depending on the affected industry.

Using the size standards from the Small Business Administration for Air Transportation and Aircraft Manufacturing, we defined companies as small entities if they have fewer than 1,500 employees.
6

6
13 CFR 121.201, Size Standards Used to Define Small Business Concerns, Sector 48-49 Transportation, Subsector 481 Air Transportation.

There are 11 U.S. aircraft manufacturers currently producing part 23 airplanes and could be affected by this proposal. These manufacturers are American Champion, Cessna, Cirrus, Eclipse, Hawker Beechcraft, Liberty, Maule, Mooney, Piper, Quest, and Sino Swearingen.

Using information provided by the World Aviation Directory, Internet filings and industry contacts, manufacturers that are subsidiary

businesses of larger businesses, manufacturers that are foreign owned, and businesses with more than 1,500 employees were eliminated from the list of entities. Cessna and Hawker Beechcraft are businesses with more than 1,500 employees and Cirrus and Liberty are foreign owned. We found no source of employment or revenue data for American Champion. For the remaining businesses, we obtained company revenue and employment from the above sources.

The base year for the proposed rule is 2008. Although the FAA forecasts traffic and air carrier fleets, we can not determine the number of new entrants nor who will be in business in the future. Therefore we use current U.S. manufacturer's revenue and employment in order to determine the number of operators this proposal would affect.

The methodology discussed above resulted in the following six U.S. part 23 aircraft manufacturers, with less than 1,500 employees, shown in Table RF1.

Table RF1

Company
Employees
Annual revenue

Quest
60
$4,600,000

Maule
86
5,700,000

Piper
100
7,600,000

Mooney
400
42,083,000

Sino Swearingen
400
25,300,000

Eclipse
1,000
36,700,000

The majority of this proposal affects the certification of turbojets and has a minor affect on the certification of turboprop and reciprocating engine airplanes by clarifying frequent non-standardization and misinterpretations of the current part 23 rules.

From the list of part 23 small entity U.S. airplane manufacturers above, only Eclipse and Sino Swearingen produce turbojet airplanes and Piper and Quest produce turboprop airplanes. The remaining part 23 small entity U.S. airplane manufacturers produce reciprocating engine airplanes.

In the regulatory evaluation, we estimated that operators of newly certificated part 23 airplanes would incur additional fuel costs. Additionally, operators could incur costs from added weight and a reduced payload capacity. The U.S. Census Bureau data on the Small Business Administration's Web site shows an estimate of the total number of small business entities who could be affected if they purchase newly certificated part 23 airplanes.
7

The U.S. Census Bureau data lists 39,754 small entities in the Non-scheduled Air Transportation Industry that employ less than 500 employees. Many of these non-scheduled businesses are in part 25. Other small businesses may own aircraft and not be included in the U.S. Census Bureau Non-scheduled Air Transportation Industry category. The estimate of the affect of this proposal on the total number of small entities that operate part 23 airplanes is developed below.

7

http://www.sba.gov/advo/research/us05_n6.pdf.

We now discuss our methodology to estimate the costs of this proposal to the small entities part 23 airplane manufacturers and operators. We will also discuss why the FAA believes this proposed rule would not result in a significant economic impact to part 23 airplane manufacturers and operators.

In 2003, we published a notice (68 FR 5488) creating the part 125/135 Aviation Rulemaking Committee (ARC). FAA and the part 23 industry have worked together to develop common certification part 23 airplane requirements proposed in this rulemaking. We contacted the part 23 aircraft manufacturers, the ARC, and General Aviation Manufacturers Association (GAMA) (an industry association for part 23 aircraft manufacturers) for specific cost estimates for each proposed section change for this rule. Not every party we contacted responded to our request for costs. Many of the ARC members, from the domestic and international manufacturing community, collaborated and filed a joint cost estimate for this proposed rule. We are basing our cost estimates for this proposed rule from these part 23 U.S. aircraft manufacturers, ARC members and GAMA.

The part 23 U.S. airplane manufacturers, ARC members, and industry association informed us that this proposed rulemaking would add manufacturer certification costs for fire extinguishing systems, climb, and take-off warning systems. Industry informed us that this proposal would save the manufacturers design time for the certification of cockpit controls. Industry has also informed us that every other proposed section of this rule is either clarifying, error correcting, or would only add minimal to no costs.

The proposed rule adds certification requirements for the following part 23 airplane categories:

1. All turbojet airplanes,

2. All turbojet airplanes with a MTOW less than 6,000 pounds,

3. All turboprop airplanes,

4. All reciprocal engine airplanes, and

5. All reciprocal twin engine airplanes with a MTOW greater than 6,000 pounds.

In some cases the proposed regulations only affect part 23 airplanes operated in revenue service. Any part 23 airplane could be used as a business airplane to haul passengers and cargo in commercial service. We estimated the business versus personal use of a part 23 airplane by analyzing the number of all US-operated airplanes from Table 3.1 of the
2006 General Aviation and Part 135 Activity Survey.
Table 3.1 shows the breakout of the 2006 General Aviation fleet by business, corporate, instructional, aerial applications, aerial observations, aerial other, external load, other work, sight see, air medical, other, part 135 Air Taxi, Air Tours, and Air Medical airplane usage. For the purpose of estimating the cost of this proposal, we assume all business part 23 airplane operators from Table 3.1 of the
2006 General Aviation and Part 135 Activity Survey
would operate in Commuter service. Table RF2 shows these results.

Table RF2—2006 General Aviation and Part 135 Activity Survey—Table 3.1

Aircraft type
Total active
Personal
% Personal
% Business

Piston
163,743
118,618
72.44
27.56

Turboprop
8,063
1,177
14.60
85.40

Turbojet
10,379
750
7.23
92.77

Table RF3 shows the results of the proposed sections that add (or subtract) incremental costs by increasing design or flight testing times, adds weight, or reducing payload.

Table RF3

Part 23 Section
Section title
Certification
Design hours
Flight test hours
Flight Operation
Additional weight
Payload reduction
Part 23 Airplane Categories Affected
Turbojet
Turbojet <6,000 # MTOW
Turboprop
Reciprocal engine
Twin reciprocal engine >6,000 # MTOW
Category

23.1193(g), 23.1195(a), 23.1197, 23.1199, 23.1201
Cowling and Nacelle, Fire Extinguisher Systems, Fire Extinguishing Agents, Extinguishing Agent Containers, Fire Extinguishing System Materials

50
25

X

Commuter.

23.63, 23.67, 23.77
Climb: General, Climb—One Engine, Balked Landing

10%

X
X

X
All.

23.703
Take-Off Warning System
1,000
25

X
X

X
All.

23.777
Cockpit Controls
−25

X

X
X

All.

We estimated part 23 airplane manufacturer fixed (added certification plus flight test hours) and operator variable (added fuel burn plus 10 percent reduction in payload) costs and applied our estimated costs to expected fleet delivered in compliance with this proposal. The total cost of this rule is the sum of the fixed certification cost plus the airplane fuel-burn variable cost multiplied by the expected fleet delivered over the analysis period.

The total fixed certification compliance cost equals the average compliance cost multiplied by the expected number of certifications of newly delivered part 23 turbojet, turboprop and reciprocating engine airplane. In the regulatory evaluation we estimated a base case and high case range for the certification costs. This range was based on the estimated number of new turbojet certifications. In the base case, we estimated five new turbojet certifications in the analysis interval. In the high case, we estimated eight new turbojet certifications. We will use the high cost case scenario for this analysis.

We estimated the certification costs for fire extinguishing systems, climb, and take-off warning systems. Based on the hours provided by the part 23 U.S. airplane manufacturers, ARC members and industry association and the
Economic Values For FAA Investment and Regulatory Decisions, A Guide
for the hourly rates.
8

Table RF4 shows the incremental certification costs estimate we calculated.

8

http://www.faa.gov/regulations_policies/policy_guidance/benefit_cost/media/050404%20Critical%20Values%20Dec%2031%20Report%2007Jan05.pdf.

Table RF4—High Cost Scenario for Part 23 Manufacturers

Costs
Recip
Commuter TP
TJ < 6,000

Design
$0
$152,020
$94,496

Design
(9,501)
(3,801)
(22,803)

Flight Test
0
114,400
93,489

Total High Cost
(9,501)
262,620
165,181

# Certifications
5
4
12

Cost per Cert
(1,900)
65,655
13,765

We applied the estimated incremental certification costs to the each of the small part 23 airplane manufacturing average number of historical certifications over a ten-year period. We then divided the small part 23 airplane

manufacturer's annual revenue by the incremental costs. Table RF5 shows these results.

Table RF5

Company
Employees

Annual
revenue

Average # certs 10 years
Airplane certificated
Estimated cert cost
Percent

Quest
60
$4,600,000
1.00
Turboprop
$65,655
1.43

Maule
86
5,700,000
0.20
Recip
−380
−0.01

Piper
100
7,600,000
1.00 (Recip) + 33 (TP)
Recip + Turboprop
65,022
0.86

Mooney
400
42,083,000
0.17
Recip
−317
0.00

Sino Swearingen
400
25,300,000
1.00
Turbojet
13,765
0.05

Eclipse
1,000
36,700,00
1.00
Turbojet
13,765
0.04

We estimated that the incremental fixed certification cost this proposed rule would be less than one percent in five of the six small entity part 23 airplane manufacturers, and less than 1.5 percent in the remaining one. We do not believe these are significant economic costs. Further, we believe that the manufacturers of the part 23 airplanes would have additional costs savings associated with the proposal standardizes and streamlining the certification process. Additional costs savings of the proposed changes to parts 1 and 23 would be to eliminate the current workload of exemptions, special conditions, and equivalent levels of safety necessary to certificate part 23 turbojets and by clarifying frequent non-standardization and misinterpretations of current part 23 rules.

To estimate the incremental variable costs to a part 23 operator, we multiplied the annual per-unit fuel burn cost by the expected fleet delivered over the analysis interval.

In the regulatory evaluation, we estimated a minimal base and high case cost for the 10 percent loss in capacity occurs the operators may incur. The base case was a no cost scenario because the average GA airplane has about 3.7 seats and flies about half full.
9

The cargo load factor for all cargo carriers is 60 percent.
10

Therefore, we conclude that the 10 percent reduction in payload caused by the proposed sections on climb and balked landings could have a minimum cost impact on part 23 airplanes for the base case. For the high case we realize that a percentage of the part 23 airplanes, in commuter service, could have a load factor over 90 percent on some of their flights. Although we believe any capacity affected would be distributed over other flights in the operator's network, we estimate the cost of a 10 percent payload capacity reduction. Table RF6 shows the results of our calculations.

9
Table 3.15 of the
Economic Values For FAA Investment and Regulatory Decisions, A Guide

10

Ibid.

Table RF6

Recip
TurboProp
Commuter TP
Total TJ
TJ<6,000

Base Case Cost
$0
$0
$8,430
$0
$0

High Case Cost
$0
$0
$1,413,692
$0
$3,086,919

Number of A/P
23,160
1,248
1,066
11,040
1,143

Base Case Cost / A/P
$0
$0
$8
$0
$0

High Case Cost / A/P
$0
$0
$1,326
$0
$2,700

A/P Value
$431,681
$3,389,054
$3,389,054
$6,300,000
$6,300,000

% Base of Value
0.00%
0.00%
0.00%
0.00%
0.00%

% High of Value
0.00%
0.00%
0.04%
0.00%
0.04%

For this proposal, our high case estimate for small business part 23 operators of turboprop airplanes would pay an additional $1,326 to operate a newly certificated airplane. Operators of newly certificated and delivered part 23 turbojet airplanes with a maximum take off weight less than 6,000 pounds would pay an additional $2,700 to operate a newly certificated airplane. Operators would not incur these costs unless they purchase a newly certificated part 23 airplane.

We do not believe that these proposals costs would be a significant impact to small entity operators because, even for the high-cost case, the compliance costs of this proposal to operators would only be 0.04 percent for a turboprop and 0.04 percent for a turbojet with a maximum take-off weight less than 6,000 pounds, of the price of a newly certificated airplane.

Therefore the FAA certifies that this proposed rule would not have a significant economic impact on a substantial number of small entities. The FAA solicits comments regarding this determination.

International Trade Impact Assessment

The Trade Agreements Act of 1979 (Pub. L. 96-39) prohibits Federal agencies from establishing any standards or engaging in related activities that create unnecessary obstacles to the foreign commerce of the United States. Legitimate domestic objectives, such as safety, are not considered unnecessary obstacles. The statute also requires consideration of international standards and, where appropriate, that they be the basis for U.S. standards. The FAA has assessed the potential effect of this final rule and has no basis for believing the rule will impose substantially different costs on domestic and international entities. Thus the FAA believes the rule has a neutral trade impact.

Unfunded Mandates Assessment

Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4) requires each Federal agency to prepare

a written statement assessing the effects of any Federal mandate in a proposed or final agency rule that may result in an expenditure of $100 million or more (in 1995 dollars) in any one year by State, local, and tribal governments, in the aggregate, or by the private sector; such a mandate is deemed to be a “significant regulatory action.” The FAA currently uses an inflation-adjusted value of $136.1 million in lieu of $100 million. This proposed rule does not contain such a mandate; therefore, the requirements of Title II of the Act do not apply.

Executive Order 13132, Federalism

The FAA has analyzed this proposed rule under the principles and criteria of Executive Order 13132, Federalism. We determined that this action would not have a substantial direct effect 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, and, therefore, would not have federalism implications.

Regulations Affecting Intrastate Aviation in Alaska

Section 1205 of the FAA Reauthorization Act of 1996 (110 Stat. 3213) requires the Administrator, when modifying regulations in Title 14, Code of Federal Regulations in a manner affecting intrastate aviation in Alaska, to consider the extent to which Alaska is not served by transportation modes other than aviation and to establish appropriate regulatory distinctions. Because this proposed rule would apply to the certification of future designs of transport category airplanes and their subsequent operation, it could, if adopted, affect intrastate aviation in Alaska. The FAA, therefore, specifically requests comments on whether there is justification for applying the proposed rule differently in intrastate operations in Alaska.

Environmental Analysis

FAA Order 1050.1E identifies FAA actions that are categorically excluded from preparation of an environmental assessment or environmental impact statement under the National Environmental Policy Act in the absence of extraordinary circumstances. The FAA has determined this proposed rulemaking action qualifies for the categorical exclusion identified in paragraph 312(f) and involves no extraordinary circumstances.

Regulations That Significantly Affect Energy Supply, Distribution, or Use

The FAA has analyzed this NPRM under Executive Order 13211, Actions Concerning Regulations that Significantly Affect Energy Supply, Distribution, or Use (May 18, 2001). We have determined that it is not a “significant energy action” under the executive order because while it is a “significant regulatory action,” it is not likely to have a significant adverse effect on the supply, distribution, or use of energy.

Additional Information

Comments Invited

The FAA invites interested persons to participate in this rulemaking by submitting written comments, data, or views. We also invite comments relating to the economic, environmental, energy, or federalism impacts that might result from adopting the proposals in this document. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. To ensure the docket does not contain duplicate comments, please send only one copy of written comments, or if you are filing comments electronically, please submit your comments only one time.

We will file in the docket all comments we receive, as well as a report summarizing each substantive public contact with FAA personnel concerning this proposed rulemaking. Before acting on this proposal, we will consider all comments we receive on or before the closing date for comments. We will consider comments filed after the comment period has closed if it is possible to do so without incurring expense or delay. We may change this proposal in light of the comments we receive.

Proprietary or Confidential Business Information

Do not file in the docket information that you consider to be proprietary or confidential business information. Send or deliver this information directly to the person identified in the
FOR FURTHER INFORMATION CONTACT
section of this document. You must mark the information that you consider proprietary or confidential. If you send the information on a disk or CD ROM, mark the outside of the disk or CD ROM, and also identify electronically within the disk or CD ROM the specific information that is proprietary or confidential.

Under 14 CFR 11.35(b), when we are aware of proprietary information filed with a comment, we do not place it in the docket. We hold it in a separate file to which the public does not have access, and we place a note in the docket that we have received it. If we receive a request to examine or copy this information, we treat it as any other request under the Freedom of Information Act (5 U.S.C. 552). We process such a request under the DOT procedures found in 49 CFR part 7.

Availability of Rulemaking Documents

You can get an electronic copy of rulemaking documents using the Internet by—

1. Searching the Federal eRulemaking Portal (
http://www.regulations.gov
);

2. Visiting the FAA's Regulations and Policies web page at
http://www.faa.gov/regulations_policies/;
or

3. Accessing the Government Printing Office's Web page at
http://www.gpoaccess.gov/fr/index.html.

You can also get a copy by sending a request to the Federal Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence Avenue SW., Washington, DC 20591, or by calling 202-267-9680. Make sure to identify the docket number or notice number of this rulemaking.

You may access all documents the FAA considered in developing this proposed rule, including economic analyses and technical reports, from the Internet through the Federal eRulemaking Portal referenced in paragraph (1).

List of Subjects

14 CFR Part 1
Air transportation.

14 CFR Part 23
Aviation Safety, Signs, Symbols, Aircraft.

The Proposed Amendments

In consideration of the foregoing, the Federal Aviation Administration proposes to amend Chapter I of Title 14, Code of Federal Regulations, as follows:

PART 1—DEFINITIONS AND ABBREVIATIONS

1. The authority citation for part 1 continues to read as follows:

Authority:

49 U.S.C. 106(g), 40113, 44701.

2. Revise the definitions of “Rated takeoff power” and “Rated takeoff thrust” and add the definitions of “Turbine engine”, “Turbojet engine”, and “Turboprop engine” in alphabetical order in § 1.1 to read as follows:

§ 1.1
General definitions.

Rated takeoff power,
with respect to reciprocating, turbopropeller, and turboshaft engine type certification, means the approved brake horsepower that is developed statically under standard sea level conditions, within the engine operating limitations established under part 33 of this chapter, and limited in use—

(1) To periods of not more than 5 minutes for takeoff operations with reciprocating, turbopropeller, and turboshaft engines; and

(2) When specifically requested by the engine manufacturer, to periods of not more than 10 minutes for one-engine-inoperative takeoff operations with turbopropeller engines.

Rated takeoff thrust,
with respect to turbojet engine type certification, means the approved turbojet thrust that is developed statically under standard sea level conditions, without fluid injection and without the burning of fuel in a separate combustion chamber, within the engine operating limitations established under part 33 of this chapter, and limited in use—

(1) To periods of not more than 5 minutes for takeoff operations; and

(2) When specifically requested by the engine manufacturer, to periods of not more than 10 minutes for one-engine-inoperative takeoff operations.

Turbine engine,
with respect to part 23 airplane type certification, consists of an air compressor, a combustion section, and a turbine. Thrust is produced by increasing the velocity of the air flowing through the engine.

Turbojet engine,
with respect to part 23 airplane type certification, is a turbine engine which produces its thrust entirely by accelerating the air through the engine.

Turboprop engine,
with respect to part 23 airplane type certification, is a turbine engine which drives a propeller through a reduction gearing arrangement. Most of the energy in the exhaust gases is converted into torque, rather than using its acceleration to drive the airplane.

PART 23—AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES

3. The authority citation for part 23 continues to read as follows:

Authority:

49 U.S.C. 106(g), 40113, 44701-44702, 44704.

4. Amend § 23.3 by revising the first sentence in paragraph (d) to read as follows:

§ 23.3
Airplane categories.

(d) The commuter category is limited to multiengine airplanes that have a seating configuration, excluding pilot seats, of 19 or less, and a maximum certificated takeoff weight of 19,000 pounds or less. * * *

5. Amend § 23.45 by revising the introductory text of paragraph (h) to read as follows:

§ 23.45
General.

(h) For multiengine turbojet powered airplanes over 6,000 pounds in the normal, utility, and acrobatic category and commuter category airplanes the following also apply:

6. Amend § 23.49 by revising the section heading and the introductory text of paragraphs (a) and (c) to read as follows:

§ 23.49
Stalling speed.

(a) V
SO
(maximum landing flap configuration) and V
S1
are the stalling speeds or the minimum steady flight speeds, in knots (CAS), at which the airplane is controllable with—

* * *

(c) Except as provided in paragraph (d) of this section, V
SO
at maximum weight may not exceed 61 knots for—

7. Amend § 23.51 by revising paragraph (b)(1) introductory text and paragraph (c) introductory text to read as follows:

§ 23.51
Takeoff speeds.

(b) * * *

(1) For multiengine airplanes, the highest of—

* * *

(c) For normal, utility, and acrobatic category multiengine turbojet airplanes of more than 6,000 pounds maximum weight and commuter category airplanes, the following apply:

8. Amend § 23.53 by revising paragraph (c) to read as follows:

§ 23.53
Takeoff performance.

(c) For normal, utility, and acrobatic category multiengine turbojet airplanes of more than 6,000 pounds maximum weight and commuter category airplanes, takeoff performance, as required by §§ 23.55 through 23.59, must be determined with the operating engine(s) within approved operating limitations.

9. Amend § 23.55 by revising the introductory text to read as follows:

§ 23.55
Accelerate-stop distance.
For normal, utility, and acrobatic category multiengine turbojet airplanes of more than 6,000 pounds maximum weight and commuter category airplanes, the accelerate-stop distance must be determined as follows:

10. Amend § 23.57 by revising the introductory text to read as follows:

§ 23.57
Takeoff path.
For normal, utility, and acrobatic category multiengine turbojet airplanes of more than 6,000 pounds maximum weight and commuter category airplanes, the takeoff path is as follows:

11. Amend § 23.59 by revising the introductory text to read as follows:

§ 23.59
Takeoff distance and takeoff run.
For normal, utility, and acrobatic category multiengine turbojet airplanes of more than 6,000 pounds maximum weight and commuter category airplanes, the takeoff distance and, at the option of the applicant, the takeoff run, must be determined.

12. Amend § 23.61 by revising the introductory text to read as follows:

§ 23.61
Takeoff flight path.
For normal, utility, and acrobatic category multiengine turbojet airplanes of more than 6,000 pounds maximum weight and commuter category airplanes, the takeoff flight path must be determined as follows:

13. Amend § 23.63 by revising the introductory text of paragraphs (c) and (d) to read as follows:

§ 23.63
Climb: General.

(c) For reciprocating engine-powered airplanes of more than 6,000 pounds maximum weight, single-engine turbines, and multiengine turbine airplanes of 6,000 pounds or less maximum weight in the normal, utility, and acrobatic category, compliance must be shown at weights as a function of airport altitude and ambient temperature, within the operational limits established for takeoff and landing, respectively, with—

(d) For multiengine turbine airplanes over 6,000 pounds maximum weight in the normal, utility, and acrobatic category and commuter category airplanes, compliance must be shown at weights as a function of airport altitude

and ambient temperature within the operational limits established for takeoff and landing, respectively, with—

14. Amend § 23.67 by:

a. Revising paragraph (b) introductory text and (b)(1) introductory text;

b. Redesignating paragraph (c) as paragraph (d)

c. Revising newly redesignated paragraph (d) introductory text, paragraph (d)(2) introductory text, paragraph (d)(3) introductory text, and paragraph (d)(4) introductory text; and

d. Adding new paragraph (c).

The revisions and addition read as follows:

§ 23.67
Climb: One-engine inoperative.

(b) For normal, utility, and acrobatic category reciprocating engine-powered airplanes of more than 6,000 pounds maximum weight, and turbopropeller-powered airplanes in the normal, utility, and acrobatic category—

(1) The steady gradient of climb at an altitude o

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3AE9-19350. Public record. Not legal advice.