[Federal Register Volume 59, Number 69 (Monday, April 11, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-8481]


[[Page Unknown]]

[Federal Register: April 11, 1994]


_______________________________________________________________________

Part II





Department of Transportation





_______________________________________________________________________



Federal Aviation Administration



_______________________________________________________________________



14 CFR Parts 27 and 29




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