[Federal Register Volume 61, Number 50 (Wednesday, March 13, 1996)]
[Rules and Regulations]
[Pages 10436-10438]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-6019]
[[Page 10435]]
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Part III
Department of Transportation
_______________________________________________________________________
Federal Aviation Administration
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14 CFR Parts 27 and 29
Airworthiness Standards; Occupant Protection in Normal and Transport
Category Rotorcraft; Final Rule
Federal Register / Vol. 61, No. 50 / Wednesday, March 13, 1996 /
Rules and Regulations
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[[Page 10436]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Parts 27 and 29
[Docket No. 27681; Amendment No. 27-32, 29-38]
RIN 2120-AE88
Airworthiness Standards; Occupant Protection in Normal and
Transport Category Rotorcraft
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: The Federal Aviation Administration (FAA) is amending the
airworthiness standards to improve occupant protection in normal and
transport category rotorcraft. These amended standards 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 also apply to
certain cargo and baggage compartments. These amendments further
complement and enhance the standards previously adopted for occupant
restraint and protection in normal and transport category rotorcraft in
the event of a survivable emergency landing.
EFFECTIVE DATE: June 11, 1996.
FOR FURTHER INFORMATION CONTACT:
Mr. Mike Mathias, Regulations Group, Rotorcraft Directorate, Aircraft
Certification Service, FAA, Forth Worth, Texas 76193-0111, telephone
number (817) 222-5110.
SUPPLEMENTARY INFORMATION:
Background
These amendments are based on Notice of Proposed Rulemaking (NPRM)
No. 94-8, which was published in the Federal Register on April 11, 1994
(59 FR 17156). That notice proposed to amend the occupant protection
airworthiness standards of 14 CFR parts 27 and 29 (parts 27 and 29) to
increase the ultimate inertial load factors in Secs. 27.561(c) and
29.561(c) and to add a new 1.5g rearward design load factor to
Secs. 27.561(b) and 29.561(b). The amended standards of Secs. 27.561(c)
and 29.561(c) would apply to restraining heavy items located above and
behind the cabin and other occupied areas against the loads created
during emergency landings; and the amended standards of Secs. 27.561(b)
and 29.561(b) would apply to restraining and protecting occupants and
restraining heavy items in the cabin and other occupied areas against
the loads created during emergency landings. In addition, the amended
standards of Secs. 27.561 (b) and (c) and 29.561 (b) and (c) would
apply to current cargo and baggage compartment standards by their
reference within the text of Secs. 27.787 and 29.787.
The Crash Resistant Fuel Systems (CRFS) in Normal and Transport
Category Rotorcraft Final Rule, Amendments 27-30 and 29-35 (59 FR
50380, October 3, 1994), amended the fuel tank and compartment
standards of Secs. 27.963 and 29.963 (which utilized the inertial
factors contained in Secs. 27.561 and 29.561, respectively) to
specifically state the CRFS inertial factor standards in
Secs. 27.952(b)(2) and 29.952(b)(2). However, the specific inertial
factors adopted in Secs. 27.952(b)(2) and 29.952(b)(2) for fuel tanks
located above or behind the occupied areas are lower than those factors
adopted in these amendments. The FAA will consider whether further
rulemaking is necessary to increase the inertial load factors for CRFS
design in Secs. 27.952(b)(2) and 29.952(b)(2) to the levels of those
adopted in Secs. 27.561(c) and 29.561(c) of these amendments.
In summary, occupant protection will be enhanced through the
increased strength requirements for retention of items of mass, such as
engines, transmissions, and baggage and cargo compartment contents
located above or behind occupied areas. These amended standards stem
from recommendations from the Aviation Rulemaking Advisory Committee
(ARAC) to increase certain design inertial load factors. These amended
standards will complement and enhance the occupant protection standards
adopted by Amendments 27-25 and 29-29 (54 FR 47310, November 13, 1989)
for survivable emergency landings.
Discussion of Comments
Interested persons have been afforded an opportunity to participate
in the making of these amendments. Due consideration has been given to
the comments received from the four commenters. The commenters are the
Civil Aviation Authority (CAA) Australia, the Airline Pilots
Association (ALPA), the Association Europeene des Constructeurs de
Material Aerospatial (AECMA), and the National Transportation Safety
Board (NTSB).
The CAA agrees that increased design inertial load factors are
appropriate but questions the logic in the difference between design
factors for occupant restraint and protection previously adopted for
interior items and the proposed factors for restraint of external
items. This commenter recommends adoption of the larger design inertial
factors found in Secs. 27.561(b) and 29.561(b) applicable to restraint
of occupants and cabin items rather than the factors proposed. The
commenter highlights the differences between the two sets of design
inertial factors.
ALPA supports the proposal but requests that the FAA determine if
the proposed 1.5g rearward inertial factor for seats is sufficient in
light of a possible emergency landing scenario in which the rotorcraft
would itself rotate 180 degrees and cause the seats and occupants to
exceed the 1.5g design inertial load factor.
AECMA notes that publication and prompt adoption of the final rule
as proposed are essential to harmonize these sections of the Federal
Aviation Regulations with the comparable European Joint Aviation
Regulations (JAR) 27 and 29 Rotorcraft Standards.
The NTSB comments that the proposed standards represent a
significant advancement in occupant protection and in crashworthiness
of normal and transport category rotorcraft and supports the proposal.
The FAA acknowledges the CAA's concern with proposed differing
design inertial factors and attempted to address these concerns in the
preamble of Notice No. 94-8 under the heading ``FAA Evaluation of ARAC
Recommendation.'' In addition, the information in Report No. DOT/FAA/
CT-85/11, ``Analysis of Rotorcraft Crash Dynamics for Development of
Improved Crashworthiness Design Criteria,'' June 1985, was the genesis
for the inertial factors contained in a previous amendment to
Secs. 27.561 and 29.561. According to that report, inertial factors for
restraint of external items can safely differ from the factors for
interior items since severe injury due to penetration into the cabin is
not identified as a significant hazard in that earlier report. However,
the increased design inertial factors proposed in Notice 94-8 will
improve both occupant protection from external items and rotorcraft
structural crashworthiness.
The FAA understands ALPA's concern about the adequacy of the 1.5g
rearward load factor in the event of an emergency landing impact in
which the rotorcraft fuselage is either fully or partially reversed for
some time interval during the overall impact sequence. Some cases of
reverse impact could exceed the proposed rearward load factor. However,
FAA research has considered the overall spectrum of reverse impacts and
that research shows that occurrences of severe, sustained reverse
impacts are remote. This
[[Page 10437]]
research also shows that reverse impacts constitute an extremely small
portion of all rotorcraft impacts. In addition, the research shows that
the gravity forces felt by occupants are significantly less in most
reverse impacts because of the larger crushing distances inherent in
most rotorcraft aft fuselage structures and because the reverse
direction of the impact is typically not sustained. Additional fuselage
motion such as tumbling and further rotation usually occur, thus the
full impact is not in a reverse direction. Therefore, the total impact
energy dissipated in a reverse impact is considered minimal. In
addition, the complementary inertial design factors in Secs. 27.561(b)
and 29.561(b), as well as the companion dynamic test standards in
Secs. 27.562 and 29.562, inherently provide strength for occupant
protection in the event of a reverse impact. Therefore, the FAA has
determined that the 1.5g rearward inertial factor is an adequate,
practical safety standard.
In response to AECMA's concern that the publication date of this
final rule correspond to the publication date of the JAR amendment, the
FAA is committed to processing this final harmonized rule so that it
can be published as near as possible to the publication date of the
JAR.
The CAA also recommends application of a 1.33 inertial attachment
factor for litter and berth installations as a logical application of
the seat design standard found in Secs. 27.785(f)(2) and 29.785(f)(2)
but recognizes that this request exceeds the scope of the proposal. The
CAA further recommends a research program to address litter
installations and litter occupant protection. To improve protection of
litter occupants, the FAA anticipates conducting an internal FAA
research program to address litter installations for airplanes and
rotorcraft.
After considering all of the comments, the FAA has determined that
air safety and the public interest require adoption of the amendments
as proposed.
Regulatory Evaluation Summary
Proposed changes to federal regulations must undergo several
economic analyses. First, Executive Order 12866 directs that each
Federal agency shall propose or adopt a regulation only upon a reasoned
determination that the benefits of the intended regulation justify its
costs. Second, the Regulatory Flexibility Act of 1980 requires agencies
to analyze the economic effect of regulatory changes on small entities.
Third, the Office of Management and Budget directs agencies to assess
the effect of regulatory changes on international trade. In conducting
these analyses, the FAA has determined that this rule: (1) Will
generate benefits exceeding its costs and is not significant as defined
in Executive Order 12866; (2) is not significant as defined in DOT's
Policies and Procedures; (3) will not have a significant impact on a
substantial number of small entities; and (4) will not affect
international trade. These analyses, available in the docket, are
summarized below.
Cost-Benefit Analysis
The increased forward, sideward, and downward load factors can be
accommodated without changing current design practices. In many cases,
sizable increases in load factors have been achieved by the use of
larger bolts and/or fasteners and minor reinforcements to attach items
of mass to the rotorcraft structure. The addition of 1.5g rearward load
factors will require no design or production modifications because the
12g and 16g forward load factors of the new and current standards will
inherently result in sufficient structural strength to meet this
rearward requirement.
Consequently, the amendments that add and revise requirements will
impose little or no incremental costs on rotorcraft manufacturers.
Additionally, they will impose no or minimal weight penalties and
operating costs on rotorcraft operators.
Occupant safety will be enhanced by the amendments, but this
enhancement is difficult to quantify. The FAA study, ``Analysis of
Rotorcraft 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 occurrences have
resulted in approximately one injury (of at least moderate severity)
per year. The benefits of averting just one such occurrence will more
than offset the negligible costs of the rule. The FAA therefore finds
the rule 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 Federal regulations. The RFA requires a
Regulatory Flexibility Analysis if a rule has significant economic
impact on a substantial number of small entities. FAA Order 2100.14A
outlines FAA's procedures and criteria for implementing the RFA. The
FAA has determined that this rule will not have a significant economic
impact on a substantial number of small manufacturers or operators of
rotorcraft because there are no small rotorcraft manufacturers, as that
term is defined in the Order.
International Trade Impact Assessment
This rule will not constitute a barrier to international trade,
including the export of American goods and services to foreign
countries and the import of foreign goods and services into the United
States. Each applicant for a new type certificate for a transport or
normal category rotorcraft, whether the applicant be U.S. or foreign,
will be required to show compliance with this rule. This rule will have
no effect on the sale of U.S. rotorcraft in foreign markets and the
sale of foreign rotorcraft in the United States.
Federalism Implications
The regulations adopted herein will 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
regulation will not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
Conclusion
For the reasons stated above, including the findings of the
Regulatory Flexibility Determination and the International Trade Impact
Analysis, the FAA has determined that this regulation is not a
significant regulatory action under Executive Order 12866. In addition,
the FAA certifies that this regulation will not have a significant
economic impact on a substantial number of small entities under the
criteria of the Regulatory Flexibility Act. This rule is not considered
significant under DOT Regulatory Policies and Procedures (44 FR 11034;
February 26, 1979). A regulatory evaluation of this regulation,
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.
[[Page 10438]]
The Amendments
Accordingly, the Federal Aviation Administration amends 14 CFR
parts 27 and 29 of the Federal Aviation Regulations 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. 106(g), 40113, 44701-44702, 44704.
2. Section 27.561 is amended by adding new paragraphs (b)(3)(v) and
(c)(5) and by 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. 106(g), 40113, 44701-44702, 44704.
4. Section 29.561 is amended by adding new paragraphs (b)(3)(v) and
(c)(5) and by 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 March 8, 1996.
David R. Hinson,
Administrator.
[FR Doc. 96-6019 Filed 3-12-96; 8:45 am]
BILLING CODE 4910-13-M
