[Federal Register Volume 70, Number 152 (Tuesday, August 9, 2005)]
[Proposed Rules]
[Pages 46113-46115]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-15659]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM316; Notice No. 25-05-11-SC]


Special Conditions: Airbus Model A380-800 Airplane, Discrete Gust 
Requirements

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This notice proposes special conditions for the Airbus A380-
800 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. Many of these 
novel or unusual design features are associated with the complex 
systems and the configuration of the airplane, including its full-
length double deck. For these design features, the applicable 
airworthiness regulations do not contain adequate or appropriate safety 
standards regarding discrete gust requirements. 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

[[Page 46114]]

issued for other novel or unusual design features of the Airbus Model 
A380-800 airplane.

DATES: Comments must be received on or before September 23, 2005.

ADDRESSES: Comments on this proposal may be mailed in duplicate to: 
Federal Aviation Administration, Transport Airplane Directorate, 
Attention: Rules Docket (ANM-113), Docket No. NM316, 1601 Lind Avenue 
SW., Renton, Washington 98055-4056; or delivered in duplicate to the 
Transport Airplane Directorate at the above address. All comments must 
be marked: Docket No. NM316. 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: Holly Thorson, FAA, International 
Branch, ANM-116, Transport Airplane Directorate, Aircraft Certification 
Service, 1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone 
(425) 227-1357; facsimile (425) 227-1149.

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 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 in light of the 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

    Airbus applied for FAA certification/validation of the 
provisionally-designated Model A3XX-100 in its letter AI/L 810.0223/98, 
dated August 12, 1998, to the FAA. Application for certification by the 
Joint Aviation Authorities (JAA) of Europe had been made on January 16, 
1998, reference AI/L 810.0019/98. In its letter to the FAA, Airbus 
requested an extension to the 5-year period for type certification in 
accordance with 14 CFR 21.17(c). The request was for an extension to a 
7-year period, using the date of the initial application letter to the 
JAA as the reference date. The reason given by Airbus for the request 
for extension is related to the technical challenges, complexity, and 
the number of new and novel features on the airplane. On November 12, 
1998, the Manager, Aircraft Engineering Division, AIR-100, granted 
Airbus' request for the 7-year period, based on the date of application 
to the JAA.
    In its letter AI/LE-A 828.0040/99 Issue 3, dated July 20, 2001, 
Airbus stated that its target date for type certification of the Model 
A380-800 has been moved from May 2005, to January 2006, to match the 
delivery date of the first production airplane. In accordance with 14 
CFR 21.17(d)(2), Airbus chose a new application date of April 20, 1999, 
and requested that the 7-year certification period which had already 
been approved be continued. The part 25 certification basis for the 
Model A380-800 airplane was adjusted to reflect the new application 
date.
    The Model A380-800 airplane will be an all-new, four-engine jet 
transport airplane with a full double-deck, two-aisle cabin. The 
maximum takeoff weight will be 1.235 million pounds with a typical 
three-class layout of 555 passengers.

Type Certification Basis

    Under the provisions of 14 CFR 21.17, Airbus must show that the 
Model A380-800 airplane meets the applicable provisions of 14 CFR part 
25, as amended by Amendments 25-1 through 25-98. If the Administrator 
finds that the applicable airworthiness regulations do not contain 
adequate or appropriate safety standards for the Airbus A380-800 
airplane because of novel or unusual design features, special 
conditions are prescribed under the provisions of 14 CFR 21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Airbus Model A380-800 airplane must comply with the 
fuel vent and exhaust emission requirements of 14 CFR part 34 and the 
noise certification requirements of 14 CFR part 36. In addition, the 
FAA must issue a finding of regulatory adequacy pursuant to section 611 
of Public Law 93-574, the ``Noise Control Act of 1972.''
    Special conditions, as defined in 14 CFR 11.19, are issued in 
accordance with 14 CFR 11.38 and become part of the type certification 
basis in accordance with 14 CFR 21.17(a)(2), Amendment 21-69, effective 
September 16, 1991.
    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 novel or 
unusual design feature, or should any other model already included on 
the same type certificate be modified to incorporate the same novel or 
unusual design features, the special conditions would also apply to the 
other model under the provisions of 14 CFR 21.101(a)(1), Amendment 21-
69, effective September 16, 1991.

Discussion of Novel or Unusual Design Features

    In terms of discrete gust requirements, the size of the Airbus 
Model A380 is a novel or unusual design feature. These requirements are 
found in 14 CFR 25.341 (Amendment 25-86) which specifies that the gust 
loads acting on the airplane are to be determined by dynamic analysis, 
considering the dynamic and rigid body responses of the airplane. 
Section 25.341(a)(3) requires that a sufficient number of gust gradient 
distances in the range of 30 feet to 350 feet be investigated to find 
the critical response for each load quantity. For large airplanes, the 
longer gust gradient distances are vital to assess the rigid body 
response.
    At the time Sec.  25.341 was adopted, the value of the upper end of 
the range of gust gradient distances to be investigated was determined 
from the largest commercial airplane then in existence, the Boeing 
Model 747. This value was calculated to be the mean geometric chord of 
the Boeing 747 (which is 28 feet) multiplied by 12.5, which equals 350 
feet.
    Since the mean geometric chord of the A380 is larger than that of 
the Boeing 747, a special condition is necessary to define an 
appropriate upper value for the range of gust gradient distances to be 
investigated. That value would be the mean geometric chord of the A380 
(which is 34.8 feet) multiplied by 12.5, which equals 435 feet. 
Increasing the range of gust gradient distances to be

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investigated to 435 feet will ensure an appropriate analysis of the 
critical rigid body response of the A380.

Applicability

    As discussed above, these special conditions are applicable to the 
Airbus A380-800 airplane. Should Airbus 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 special conditions 
would apply to that model as well under the provisions of Sec.  
21.101(a)(1), Amendment 21-69, effective September 16, 1991.

Conclusion

    This action affects only certain novel or unusual design features 
of the Airbus A380-800 airplane. It is not a rule of general 
applicability, and it affects only the applicant which applied to the 
FAA for approval of these features on the airplane.

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, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration (FAA) proposes the 
following special conditions as part of the type certification basis 
for the Airbus A380-800 airplane.
    In lieu of the requirements of Sec.  25.341(a)(3), the following 
special conditions apply:
    A sufficient number of gust gradient distances in the range of 30 
feet to 435 feet (12.5 times the Geometric Mean Chord of the Model 
A380) must be investigated to find the critical response for each load 
quantity.

    Issued in Renton, Washington, on July 19, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-15659 Filed 8-8-05; 8:45 am]
BILLING CODE 4910-13-P