Special Conditions: Boeing Model 787-8 Airplane; Crashworthiness, 32021-32023 [E7-11153]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 72, Number 111 (Monday, June 11, 2007)]
[Proposed Rules]
[Pages 32021-32023]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-11153]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM368 Special Conditions No. 25-07-05-SC]


Special Conditions: Boeing Model 787-8 Airplane; Crashworthiness

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This notice proposes special conditions for the Boeing Model 
787-8 airplane. This airplane will have novel or unusual design 
features when compared to the state of technology envisioned in the 
airworthiness standards for transport category airplanes. These novel 
or unusual design features are associated with carbon fiber reinforced 
plastic used in the construction of the fuselage. For these design 
features, the applicable airworthiness regulations do not contain 
adequate or appropriate safety standards for impact response 
characteristics to ensure survivable crashworthiness. These proposed 
special conditions contain the additional safety standards that the 
Administrator considers necessary to establish a level of safety 
equivalent to that established by the existing airworthiness standards. 
Additional special conditions will be issued for other novel or unusual 
design features of the Boeing 787-8 airplanes.

DATES: Comments must be received on or before July 26, 2007.

ADDRESSES: Comments on this proposal may be mailed in duplicate to: 
Federal Aviation Administration, Transport Airplane Directorate, 
Attention: Rules Docket (ANM-113), Docket No. NM368, 1601 Lind Avenue 
SW., Renton, Washington 98057-3356; or delivered in duplicate to the 
Transport Airplane Directorate at the above address. All comments must 
be marked Docket No. NM368. Comments may be inspected in the Rules 
Docket weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Ian Won, FAA, Airframe/Cabin Safety, 
ANM-115, Transport Airplane Directorate, Aircraft Certification 
Service, 1601 Lind Avenue SW., Renton, Washington 98057-3356; telephone 
(425) 227-2145; facsimile (425) 227-1320.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites interested persons to participate in this 
rulemaking by submitting written comments, data, or views. The most 
helpful comments reference a specific portion of the special 
conditions, explain the reason for any recommended change, and include 
supporting data. We ask that you send us two copies of written 
comments.
    We will file in the docket all comments we receive as well as a 
report summarizing each substantive public

[[Page 32022]]

contact with FAA personnel concerning these proposed special 
conditions. The docket is available for public inspection before and 
after the comment closing date. If you wish to review the docket in 
person, go to the address in the ADDRESSES section of this notice 
between 7:30 a.m. and 4 p.m., Monday through Friday, except Federal 
holidays.
    We will consider all comments we receive on or before the closing 
date for comments. We will consider comments filed late if it is 
possible to do so without incurring expense or delay. We may change the 
proposed special conditions based on comments we receive.
    If you want the FAA to acknowledge receipt of your comments on this 
proposal, include with your comments a pre-addressed, stamped postcard 
on which the docket number appears. We will stamp the date on the 
postcard and mail it back to you.

Background

    On March 28, 2003, Boeing applied for an FAA type certificate for 
its new Boeing Model 787-8 passenger airplane. The Model 787-8 airplane 
will be an all-new, two-engine jet transport airplane with a two-aisle 
cabin. The maximum takeoff weight will be 476,000 pounds, with a 
maximum passenger count of 381 passengers.

Type Certification Basis

    Under provisions of 14 CFR 21.17, Boeing must show that Model 787-8 
airplanes (hereafter referred to as ``the 787'') meet the applicable 
provisions of 14 CFR part 25, as amended by Amendments 25-1 through 25-
117, except Sec. Sec.  25.809(a) and 25.812, which will remain at 
Amendment 25-115. If the Administrator finds that the applicable 
airworthiness regulations do not contain adequate or appropriate safety 
standards for the 787 airplane because of a novel or unusual design 
feature, special conditions are prescribed under provisions of 14 CFR 
21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the 787 airplane must comply with the fuel vent and exhaust 
emission requirements of 14 CFR part 34 and the noise certification 
requirements of part 36. In addition, the FAA must issue a finding of 
regulatory adequacy pursuant to section 611 of Public Law 92-574, the 
``Noise Control Act of 1972.''
    Special conditions, as defined in Sec.  11.19, are issued in 
accordance with Sec.  11.38 and become part of the type certification 
basis in accordance with Sec.  21.17(a)(2).
    Special conditions are initially applicable to the model for which 
they are issued. Should the type certificate for that model be amended 
later to include any other model that incorporates the same or similar 
novel or unusual design feature, the special conditions would also 
apply to the other model under the provisions of Sec.  21.101.

Novel or Unusual Design Features

    The 787 airplane will incorporate a number of novel or unusual 
design features. Because of rapid improvements in airplane technology, 
the applicable airworthiness regulations do not contain adequate or 
appropriate safety standards for these design features. These proposed 
special conditions for the 787 contain the additional safety standards 
that the Administrator considers necessary to establish a level of 
safety equivalent to that established by the existing airworthiness 
standards.
    The 787 fuselage will be fabricated with carbon fiber reinforced 
plastic (CFRP) semi-monocoque construction, consisting of skins with 
co-cured longitudinal stringers and mechanically fastened 
circumferential frames. This is a novel and unusual design feature for 
a large transport category airplane certificated under 14 CFR part 25. 
Structure fabricated from CFRP may behave differently than metallic 
structure because of differences in material ductility, stiffness, 
failure modes, and energy absorption characteristics. Therefore, impact 
response characteristics of the 787 must be evaluated to ensure that 
its survivable crashworthiness characteristics provide approximately 
the same level of safety as those of a similarly sized airplane 
fabricated from traditionally used metallic materials.
    The FAA and industry have been working together for many years to 
understand how transport airplane occupant safety can be improved for 
what are considered survivable accidents. This work has involved 
examining airplane accidents, conducting tests to simulate crash 
conditions, and performing analytical modeling of a range of crash 
conditions, all with the purpose of providing further insight into 
factors that can influence occupant safety. Results of this on-going 
effort have enabled specific changes to regulatory standards and design 
practices to improve occupant safety. This evolution is reflected in 
changes to the part 25 Emergency Landing Conditions regulations. For 
example, airplane emergency load factors in Sec.  25.561, General, have 
been increased. Passenger seat dynamic load conditions have been added 
(Sec.  25.562, Emergency Landing Dynamic Conditions).
    The seat dynamic conditions were added to the regulations based on 
FAA and industry tests and a review of accidents. These seat dynamic 
conditions reflect the environment for passengers and the airframe 
during a crash event. They are based on data gathered from accidents of 
previously certificated airplanes given conditions that were 
survivable. Tests of previously certificated airplanes demonstrated 
that performance of the airframe was acceptable in a survivable crash 
event. We continually update our requirements as such new information 
becomes available. In the context of this evolution of the regulations, 
there is at present no specific dynamic regulatory requirement for 
airplane-level crashworthiness. However, the FAA reviews the design of 
each new airplane model to determine if it incorporates novel or 
unusual design features that may have a significant influence on the 
crash dynamics of the airframe. The Administrator prescribes special 
conditions for the airplane model if the applicable airworthiness 
regulations do not contain adequate or appropriate safety standards 
because of the novel or unusual design feature. Because of the novel 
design features of the 787, the FAA intends to require Boeing to 
conduct an assessment to ensure that the 787 will not have dynamic 
characteristics that differ significantly from those found in 
previously certificated designs.
    The nature of this proposed design assessment is largely dependent 
on the similarities and differences between the new type design and 
previously certificated airplanes. Such an assessment ensures that the 
level of safety of the new type design is commensurate with that 
implicitly assumed in the existing regulations, and achieved by 
airplane designs previously certificated. If significant trends in 
industry warrant change to the existing regulations, the FAA may use 
its rulemaking process in collaboration with industry to develop an 
appropriate dynamic regulatory requirement for airplane level 
crashworthiness.
    The FAA and industry have collected a significant amount of 
experimental data as well as data from crashes of transport category 
airplanes that demonstrates a high occupant survival rate at vertical 
descent velocities up to 30 ft/sec. The majority of this data was 
collected on narrow-body (single aisle) transport category airplanes. 
Based on this information, the FAA finds it appropriate and necessary 
for an assessment of the 787 to span a range of

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airplane vertical descent velocities up to 30 ft/sec.
    The FAA is proposing this special condition to maintain the level 
of safety envisioned in the existing airworthiness standards under 
foreseeable survivable impact events.

Discussion of Proposed Special Condition

    In order to provide the same level of safety as exists with 
conventional airplane construction, Boeing must demonstrate that the 
787 has sufficient crashworthiness capabilities under foreseeable 
survivable impact events. To demonstrate this, Boeing would have to 
evaluate the impact response characteristics of the 787 to ensure that 
its crashworthiness characteristics are not significantly different 
from those of a similarly sized airplane fabricated from traditionally 
used metals. If the evaluation shows that the 787 impact response 
characteristics are significantly different, Boeing would have to make 
design changes to bring the different impact response characteristics 
in line with those of a similarly sized metal construction airplane, or 
incorporate mitigating design features.
    Factors in crash survivability are retention of items of mass, 
maintenance of occupant emergency egress paths, maintenance of 
acceptable acceleration and loads experienced by the occupants, and 
maintenance of a survivable volume. In reviewing available data from 
accidents, tests simulating crash conditions, and analytical modeling 
of a range of crash conditions, the FAA has concluded that the airplane 
performance should be evaluated over a range of airplane level vertical 
impact velocities up to 30 ft/sec.
    If the 787 impact characteristics differ significantly from those 
of a previously certificated wide body transport, this would result in 
a need to meet load factors higher than those defined in 14 CFR 25.561 
in order to maintain the same level of safety for the occupants, in 
terms of retention of items of mass. In the cases of acceleration and 
loads experienced by the occupants, means would have to be incorporated 
to reduce load levels experienced by those occupants to the injury 
criteria levels of Sec.  25.562, or load levels of a previously 
certificated comparable airplane, in order to maintain the same level 
of safety for the occupants.

Applicability

    As discussed above, these proposed special conditions are 
applicable to the 787 airplane. Should Boeing apply at a later date for 
a change to the type certificate to include another model incorporating 
the same novel or unusual design features, these proposed special 
conditions would apply to that model as well under the provisions of 
Sec.  21.101.

Conclusion

    This action affects only certain novel or unusual design features 
of the 787 airplane. It is not a rule of general applicability.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

    The authority citation for these Special Conditions is as follows:

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

The Proposed Special Conditions

    Accordingly, the Administrator of the Federal Aviation 
Administration (FAA) proposes the following special conditions as part 
of the type certification basis for the Boeing Model 787-8 airplane.
    The Boeing Model 787-8 must provide an equivalent level of occupant 
safety and survivability to that provided by previously certificated 
wide-body transports of similar size under foreseeable survivable 
impact events for the following four criteria. In order to demonstrate 
an equivalent level of occupant safety and survivability, the applicant 
must demonstrate that the Model 787-8 meets the following criteria for 
a range of airplane vertical descent velocities up to 30 ft/sec.
    1. Retention of items of mass. The occupants, i.e., passengers, 
flight attendants and flightcrew, must be protected during the impact 
event from release of seats, overhead bins, and other items of mass due 
to the impact loads and resultant structural deformation of the 
supporting airframe and floor structures. The applicant must show that 
loads due to the impact event and resultant structural deformation of 
the supporting airframe and floor structure at the interface of the 
airplane structure to seats, overhead bins, and other items of mass are 
comparable to those of previously certificated wide-body transports of 
similar size for the range of descent velocities stated above. The 
attachments of these items need not be designed for static emergency 
landing loads in excess of those defined in Sec.  25.561 if impact 
response characteristics of the Boeing Model 787-8 yield load factors 
at the attach points that are comparable to those for a previously 
certificated wide-body transport category airplane.
    2. Maintenance of acceptable acceleration and loads experienced by 
the occupants. The applicant must show that the impact response 
characteristics of the 787, specifically the vertical acceleration 
levels experienced at the seat/floor interface and loads experienced by 
the occupants during the impact events, are consistent with those found 
in Sec.  25.562(b) or with levels expected for a previously 
certificated wide-body transport category airplane for the conditions 
stated above.
    3. Maintenance of a survivable volume. For the conditions stated 
above, the applicant must show that all areas of the airplane occupied 
for takeoff and landing provide a survivable volume comparable to that 
of previously certificated wide-body transports of similar size during 
and after the impact event. This means that structural deformation will 
not result in infringement of the occupants' normal living space so 
that passenger survivability will not be significantly affected.
    4. Maintenance of occupant emergency egress paths. The evacuation 
of occupants must be comparable to that from a previously certificated 
wide-body transport of similar size. To show this, the applicant must 
show that the suitability of the egress paths, as determined following 
the vertical impact events, is comparable to the suitability of the 
egress paths of a comparable, certificated wide-body transport, as 
determined following the same vertical impact events.

    Issued in Renton, Washington, on May 31, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E7-11153 Filed 6-8-07; 8:45 am]
BILLING CODE 4910-13-P