Airworthiness Standards; Occupant Protection in Normal and Transport Category Rotorcraft; Proposed Rule

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 27 and 29

[Docket No. 27681; Notice No. 94-8]

RIN 2120-AE88

Airworthiness Standards; Occupant Protection in Normal and

Transport Category Rotorcraft

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to improve occupant protection standards in

normal and transport category rotorcraft. The proposed standards would

significantly increase the static design ultimate inertial load factors

for restraining heavy items located above or behind the occupied areas

during emergency landings. These increased load factors would also

apply to certain fuel, cargo, and baggage compartments. These proposals

would further enhance occupant protection and complement the standards

previously adopted for occupant restraint in normal and transport

category rotorcraft in the event of a survivable emergency landing.

DATES: Comments must be received on or before July 11, 1994.

ADDRESSES: Comments on this notice should be mailed or delivered in

triplicate to: Federal Aviation Administration (FAA), Office of the

Chief Counsel, Attn: Rules Docket (AGC-10), Docket No. 27681, 800

Independence Avenue, SW., Washington, DC 20591. Comments may be

examined in Room 915G weekdays between 9 a.m. and 5 p.m., except

Federal holidays.

FOR FURTHER INFORMATION CONTACT:

Mr. James H. Major, Regulations Group (ASW-111), Rotorcraft

Directorate, Aircraft Certification Service, FAA, Fort Worth, Texas

76193-0111, telephone number (817) 624-5117.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to submit written data, views, or

arguments on this proposed rule. Comments relating to the

environmental, energy, federalism, or economic impact that might result

from adopting the proposals in this notice are also invited.

Substantive comments should be accompanied by cost estimates. Comments

should identify the regulatory docket number and should be submitted in

triplicate to the Rules Docket address specified above. All

communications received on or before the closing date for comments will

be considered by the Administrator before taking action on this

proposed rule. The proposals contained in this notice may be changed in

light of the comments received. All comments received will be

available, both before and after the closing date for comments, in the

Rules Docket for examination by interested persons. A report

summarizing each substantive public contact with FAA personnel

concerned with this rulemaking will be filed in the docket. Commenters

wishing the FAA to acknowledge receipt of their comments submitted in

response to this notice must include a preaddressed, stamped postcard

on which the following statement is made: ``Comments to Docket No.

27681.'' The postcard will be date stamped and mailed to the commenter.

Availability of NPRM's

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

to the FAA, Office of Public Affairs, Attn: Public Inquiry Center, APA-

200, 800 Independence Avenue, SW., Washington, DC 20591, or by calling

(202) 267-3484. Communications must identify the notice number of this

NPRM.

Persons interested in being placed on a mailing list for future

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

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

describes the application procedures.

Background

On June 3, 1987, the FAA issued NPRM No. 87-4 (52 FR 20938) to

amend the rotorcraft airworthiness standards to improve occupant

protection in the event of a survivable emergency landing. Comments and

alternative proposals were received at a public meeting on April 20,

1988, in Fort Worth, Texas. Written comments and alternative proposals

submitted are contained in Rules Docket No. 25287.

As part of the notice, the FAA proposed that Federal Aviation

Regulations (FAR) Secs. 27.561(c) and 29.561(c) contain an increased

``forward'' static design ultimate inertial load factor (load factor)

for external items of mass located above or behind the occupants. The

increased load factors proposed by Notice No. 87-4 were based on

information in Report No. DOT/FAA/CT-85/11, ``Analysis of Rotorcraft

Crash Dynamics for Development of Improved Crashworthiness Design

Criteria,'' June 1985. This report is contained in Rules Docket No.

25287. In comments to NPRM No. 87-4, the Aerospace Industries

Association (AIA) and others recommended increasing the existing load

factors for sideward and downward loads and further increasing the

proposed forward load factor. These recommendations were more

restrictive than the standards proposed and could not be adopted

without proper public notice and procedure. The proposals in Notice No.

87-4 were adopted as a final rule in Amendments 27-25 and 29-29 (54 FR

47310, November 13, 1989). The FAA stated in the preamble to the final

rule that it would consider the comments to Notice No. 87-4 as a basis

in any future rulemaking activity.

On February 13, 1992, following an announcement in the Federal

Register (56 FR 63545, December 4, 1991), a working group chartered by

the Aviation Rulemaking Advisory Committee (ARAC) met to consider

certain recommendations submitted to Rules Docket 25287. The working

group, chaired by a representative from AIA, included technical

specialists in crash dynamics loads and design criteria from two major

helicopter manufacturers and representatives from the National Business

Aircraft Association (NBAA), Helicopter Association International

(HAI), Emergency Medical Services (EMS), and the FAA Rotorcraft

Directorate. This broad participation is consistent with FAA policy to

have all known interested parties involved as early as practicable in

the rulemaking process.

Two tasks were assigned by the ARAC to the working group, as

follows:

Task 1

Determine the need for new or revised standards and make a

recommendation concerning whether the design load factors should be

increased for items of mass located above and behind, above, or behind

the passenger compartment.

Task 2

Determine the need for new or revised standards and make a

recommendation concerning whether Secs. 27.785(f)(2) and 29.785(f)(2)

should be clarified to specify the 1.33 fitting factor for seats also

applies to berths and litters.

ARAC Task 1 Synopsis

The working group explored the merits of the increases in load

factors and of an additional rearward load factor of 1.5g. Discussion

centered on the potential increase in safety, current design practices,

weight impact, and benefit versus cost of the proposed changes.

At the request of the ARAC working group, a manufacturer's

technical specialist explained how the AIA ascertained the following

proposed increased load factors: a forward load factor increase from 8g

to 12g, a sideward load factor increase from 2g to 6g, and a downward

load factor increase from 4g to 12g.

An AIA rotorcraft committee reached a consensus on the proposed

load factors after determining that the increased load factors are more

compatible with occupant restraint requirements than are current load

factors for items of mass. This determination of increased load factors

for items of mass included a review which showed that current design

practices to meet stiffness and fatigue requirements provide sufficient

backup structure to restrain items of mass with minimal increase in

attachment strength requirements. This committee proposed increases in

the required load factors that would enhance occupant safety without

introducing changes to current design practices.

The ARAC working group concluded that safety would be enhanced by

the proposed changes. The number of lives saved could not be quantified

from information available to the AIA Crash Dynamics working group that

was formed before issuance of NPRM No. 87-4. The ARAC working group

agreed that the potential for increased safety resulting from the

changes justified the need for preparing an FAA benefits and cost

comparison. A summary of the resulting benefits and cost comparison is

included in this notice.

The ARAC working group determined that the proposal to add a new

1.5g rearward load factor would: (1) Provide an appropriate structural

design condition for seats and (2) enhance safety. They also determined

that the cost impact would be minimal because the proposed 12g forward

load factor would provide inherently a 1.5g rearward capability.

The ARAC working group determined that certification costs for

analysis or tests to substantiate compliance with the proposed changes

would be negligible. Further, the working group technical specialists

agreed that the increased load factors would have minimal and in some

cases no weight impact on a new rotorcraft design, particularly when

current design practices are considered.

ARAC Task 2 Synopsis

The working group studied the use of a 1.33 attachment factor for

litters and berths. Accident and incident data from EMS helicopter

operations obtained from a major helicopter manufacturer were

presented. The information showed that occupants of litters experienced

fewer severe injuries and fatalities than seated helicopter occupants

in comparable accidents. Additionally, it was noted that part 25

transport airplane standards (Sec. 25.785(f)(3)) do not apply the 1.33

attachment factor to berths or litters, and no significant need for

increased crashworthiness for large airplanes has been documented;

i.e., no one has proposed the addition of the 1.33 attachment factor to

Sec. 25.785(f). The ARAC working group concluded, based on an analysis

of rotorcraft accident information and similar standards in part 25,

that the current airworthiness standards provide a high level of

safety, and that a change in the litter and berth standards to add the

1.33 attachment factor is not necessary at this time.

However, during an ARAC meeting, a European Joint Airworthiness

Authority (JAA) representative requested that the FAA defer any

decision while the JAA reviews the accident and incident data. The JAA

suggested that data may reveal a relationship between the possible

application of a 1.33 attachment factor and the lack of serious

occupant injuries; that is, a 1.33 attachment factor may be already

included in most current designs. Therefore, this proposal is being

deferred to provide for additional review by the JAA and for possible

consideration in a future ARAC project.

ARAC Summary

The working group, and subsequently the ARAC, recommended that the

FAA revise the certification standards for normal and transport

category rotorcraft by increasing the load factor requirements in

Secs. 27.561(c) and 29.561(c). Specifically, the ARAC recommended the

following changes: a forward load factor increase from 8g to 12g, a

sideward load factor increase from 2g to 6g, a downward load factor

increase from 4g to 12g, and the addition of a new rearward load factor

of 1.5g. ARAC also recommended adding a new rearward load factor of

1.5g to Secs. 27.561(b) and 29.561(b).

FAA Evaluation of ARAC Recommendation

The FAA has reviewed the information contained in the ARAC

recommendation in conjunction with comments to Notice of Proposed

Rulemaking (NPRM) No. 87-4. During this review the FAA evaluated the

tests and analyses that support load factors higher than those proposed

in NPRM No. 87-4; these are the load factors proposed in this notice.

The FAA specifically evaluated comments to NPRM No. 87-4 by the AIA and

the British Civil Aviation Authority (CAA). These comments are

contained in Rules Docket No. 25287. The AIA and CAA comments include

various new and increased load factors ranging from 9g to 12g for a

forward load factor and 6.5g to 12g for a downward load factor that

were evaluated by the ARAC. The ARAC review of these various load

factors resulted in a proposal to increase the forward load factor from

8g to 12g, the sideward load factor from 2g to 6g, the downward load

factor from 4g to 12g, and to add a new rearward load factor of 1.5g.

The new and increased load factors can be met by current rotorcraft

designs with small increases in attachment sizes and with the resultant

minimum increase in cost.

The FAA concluded that the ARAC proposals incorporate the best

combination of new and increased load factors recommended in the AIA

and CAA proposals. Crashworthiness would be improved through

significant increases in strength for retention of items of mass, such

as engines and transmissions, with negligible increases in cost and

weight. Also, the FAA evaluation showed that the increased factors for

retention of items of mass complement the higher load factors for

occupant restraint contained in Secs. 27.561(b) and 29.561(b).

Accordingly, the FAA has determined that the benefits of increasing the

load factors for items of mass located above or behind occupied areas

would outweigh any cost of providing the necessary increased attachment

and support strength.

Discussion of Related Rules

After the working group's meeting and deliberations, the FAA

determined that it would be helpful to clarify the intent of the

group's proposals relative to current cargo and baggage compartment

standards. Amendments 27-27 and 29-31 (55 FR 38966, September 21, 1990)

to Secs. 27.787 and 29.787, respectively, require cargo and baggage

compartments to restrain the compartment contents under emergency

landing conditions to the extent of the load factors as specified in

Secs. 27.561 and 29.561. The FAA is not proposing amending these

sections but is providing clarification for application of the proposed

changes relative to the current cargo and baggage compartment standards

of Secs. 27.787 and 29.787. Since baggage and cargo compartments may be

located in the passenger compartment under certain operating rules,

such compartments must meet the load factor requirements in

Secs. 27.561(b) or 29.561(b). Other cargo and baggage compartments if

located ``above or behind the new passenger compartment'' must meet the

load factor requirements in Secs. 27.561(c) or 29.561(c) in accordance

with Secs. 27.787 and 29.787.

General Discussion of the Proposals

Normal and transport category rotorcraft are subject to comparable

emergency landing conditions and, therefore, are subject to the same

level of occupant protection contained in the emergency landing

standards in Secs. 27.561 and 29.561. These proposals, if adopted,

respond to the recommendations for increased load factors and

supplement the occupant protection standards in Amendments 27-25 and

29-29. The European Joint Airworthiness Authorities committee concurs

with these proposals.

Sections 27.561 and 29.561

Sections 27.561 and 29.561 would be amended by adding a new

paragraph (b)(3)(v) that would require seats and items of mass to

sustain a rearward load resulting from a 1.5g load factor. This would

further protect occupants from impact with injurious objects behind the

occupant in the event of an accident. Also, the load factors of

paragraphs (c) (2), (3), and (4) would be increased, and paragraph (5)

would be added as recommended by the ARAC. These increased load factors

would enhance protection of occupants from items of mass including

cargo and baggage compartments located above or behind the crew and

passenger compartment.

Regulatory Evaluation Summary

Introduction

Proposed changes to Federal regulations must undergo several

economic analyses. First, Executive Order 12866 directs Federal

agencies to promulgate new regulations or modify existing regulations

only if the potential benefits to society outweigh the potential costs.

Second, the Regulatory Flexibility Act of 1980 requires agencies to

analyze the economic impact of regulatory changes on small entities.

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

the effects of regulatory changes on international trade. In conducting

these analyses or assessments, the FAA has determined that this rule:

(1) Would generate benefits exceeding its costs and is nonsignificant

as defined in Executive Order 12866; (2) is not significant as defined

in DOT's Policies and Procedures; (3) would not have a significant

impact on a substantial number of small entities; and (4) would not

affect international trade. These analyses, available in the docket,

are summarized below.

Costs

As noted previously, the increased forward, sideward, and downward

load factors could be accommodated without introducing changes to

current design practices. In many cases, sizeable increases in load

factors have been met by the use of larger bolts and/or fasteners and

minor reinforcements to attach items of mass to the rotorcraft

structure. The proposed addition of 1.5g rearward load factors for

items of mass outside or inside the cabin would require no production

modifications because the 12g and 16g forward load factors would

inherently result in sufficient structural strength to meet the 1.5g

rearward requirement.

Consequently, the proposed revisions and amendments would impose

little or no incremental costs on rotorcraft manufacturers.

Additionally, they would impose no or minimal weight penalties and

operating costs on rotorcraft operators.

Benefits

Occupant safety would be enhanced by the proposals, but is

difficult to quantify. The FAA study, ``Analysis of Rotocraft Crash

Dynamics for Development of Improved Crashworthiness Design Criteria''

(Report No. DOT/FAA/CT-85/11, June 1985), identified separation of

items of mass from the rotorcraft structure and penetration into

occupied areas as one of 14 hazards associated with otherwise

survivable rotorcraft accidents. Such penetration occurrences resulted

in approximately one injury (at least moderate) per year. The benefits

of averting just one such occurrence would more than offset the

negligible costs of the proposed rule. The FAA, therefore, finds the

proposed changes to be cost beneficial.

Regulatory Flexibility Determination

The Regulatory Flexibility Act of 1980 (RFA) was enacted by

Congress to ensure that small entities are not unnecessarily and

disproportionately burdened by government regulations. The RFA requires

a Regulatory Flexibility Analysis if a rule has a significant economic

impact, either detrimental or beneficial, on a substantial number of

small entities. Based on the criteria of FAA Order 2100.14A, Regulatory

Flexibility Criteria and Guidance, the FAA has determined that the

proposed rule would not have a significant economic impact on a

substantial number of small manufacturers or operators of rotorcraft.

International Trade Impact Assessment

The proposed rule would have no effect on the sale of foreign

products domestically or the sale of U.S. products in foreign markets.

Federalism Implications

The regulations proposed by this notice would not have substantial

direct effects on the states, on the relationships between the national

government and the states, or on the distribution of power and

responsibilities among the various levels of government. Therefore, in

accordance with Executive Order 12612, it is determined that this

proposal would not have sufficient federalism implications to warrant

the preparation of a Federalism Assessment.

Conclusion

For the reasons stated above, including the findings in the

Regulatory Flexibility Determination and the International Trade Impact

Analysis, the FAA has determined that this proposed regulation is not a

significant regulatory action under Executive Order 12866. In addition,

the FAA certifies that this proposal, if adopted, will not have a

significant economic impact, positive or negative, on a substantial

number of small entities under the criteria of the Regulatory

Flexibility Act. This proposal is not considered significant under DOT

Regulatory Policies and Procedures (44 FR 11034; February 26, 1979). An

initial regulatory evaluation of the proposal, including a Regulatory

Determination and Trade Impact Analysis, has been placed in the docket.

A copy may be obtained by contacting the person identified under the

section entitled ``FOR FURTHER INFORMATION CONTACT.''

List of Subjects in 14 CFR Parts 27 and 29

Air transportation, Aircraft, Aviation safety, Rotorcraft, Safety.

The Proposed Amendments

Accordingly, the Federal Aviation Administration proposes to amend

parts 27 and 29 of the Federal Aviation Regulations (14 CFR parts 27

and 29) as follows:

PART 27--AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT

1. The authority citation for part 27 continues to read as follows:

Authority: 49 U.S.C. 1344, 1354(a), 1355, 1421, 1423, 1425,

1428, 1429, 1430; and 49 U.S.C. 106(g).

2. Section 27.561 is amended by adding new paragraphs (b)(3)(v) and

(c)(5) and revising paragraphs (c)(2), (c)(3), and (c)(4) to read as

follows:

Sec. 27.561 General.

* * * * *

(b) * * *

(3) * * *

(v) Rearward--1.5g

(c) * * *

(2) Forward--12g

(3) Sideward--6g

(4) Downward--12g

(5) Rearward--1.5g

PART 29--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT

3. The authority citation for part 29 continues to read as follows:

Authority: 49 U.S.C. 1344, 1354(a), 1355, 1421, 1423, 1424,

1425, 1428, 1429, 1430; and 49 U.S.C. 106(g).

4. Section 29.561 is amended by adding new paragraphs (b)(3)(v) and

(c)(5) and revising paragraphs (c)(2), (c)(3), and (c)(4) to read as

follows:

Sec. 29.561 General.

* * * * *

(b) * * *

(3) * * *

(v) Rearward--1.5g

(c) * * *

(2) Forward--12g

(3) Sideward--6g

(4) Downward--12g

(5) Rearward--1.5g

* * * * *

Issued in Washington, DC, on April 4, 1994.

Elizabeth Yoest,

Acting Director, Aircraft Certification Service.

[FR Doc. 94-8481 Filed 4-8-94; 8:45 am]

BILLING CODE 4910-13-M