[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]
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Part II
Department of Transportation
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Federal Aviation Administration
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14 CFR Parts 27 and 29
Airworthiness Standards; Occupant Protection in Normal and Transport
Category Rotorcraft; Proposed Rule
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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).
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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
