[Federal Register Volume 71, Number 15 (Tuesday, January 24, 2006)]
[Rules and Regulations]
[Pages 3753-3754]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-598]



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 Rules and Regulations
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  Federal Register / Vol. 71, No. 15 / Tuesday, January 24, 2006 / 
Rules and Regulations  

[[Page 3753]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM316; Special Conditions No. 25-312-SC]


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued 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 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 Airbus Model 
A380-800 airplane.

EFFECTIVE DATE: The effective date of these special conditions is 
January 10, 2006.

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: 

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).
    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, the special conditions would also apply to the 
other model under the provisions of 14 CFR 21.101.

Discussion of Novel or Unusual Design Features

    In terms of requirements pertaining to discrete gusts, 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.

[[Page 3754]]

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

Discussion of Comments

    Notice of Proposed Special Conditions No. 25-05-11-C, pertaining to 
discrete gust requirements for the Airbus A380 airplane, was published 
in the Federal Register on August 9, 2005 (70 FR 46113). A single 
comment was received which supports the intent and the language of the 
special condition, as proposed.

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.

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.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.


0
The authority citation for these special conditions is as follows:

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

The Special Conditions

0
Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration (FAA), the following 
special conditions are issued 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 Chord of the Model A380) 
must be investigated to find the critical response for each load 
quantity.

    Issued in Renton, Washington, on January 10, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 06-598 Filed 1-23-06; 8:45 am]
BILLING CODE 4910-13-M