[Federal Register Volume 70, Number 152 (Tuesday, August 9, 2005)]
[Proposed Rules]
[Pages 46106-46108]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-15655]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM321; Notice No. 25-05-16-SC]


Special Conditions: Airbus Model A380-800 Airplane, Ground 
Turning Loads

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 ground turning loads. 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 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. NM321, 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. NM321. 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

[[Page 46107]]

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

    The A380 has a landing gear arrangement consisting of a nose gear, 
two wing mounted gears, and two body mounted gears. This is different 
from the conventional tricycle landing gear arrangement envisioned by 
14 CFR 25.495. The simple load condition specified in Sec.  25.495, 
while providing a realistic approximation for designing a tricycle 
landing gear arrangement, will give unrealistic results for the A380. 
Safe sizing of the A380 landing gears necessitates a rational ground 
turning analysis that considers the way the airplane as a whole 
responds to a turning maneuver.
    Furthermore, recent studies of the current generation of transport 
category airplanes carried out in the U.S. and in Europe indicate a 
correlation between lower load factors in ground turns and higher gross 
weight of an airplane. This correlation was documented in the FAA-
sponsored report, DOT/FAA/AR-02/129 Side Load Factor Statistics from 
Commercial Aircraft Ground Operations, dated January 2003. As stated in 
the report's abstract, ``The results of this study clearly indicate, 
however, that the lateral loads experienced by the larger/heavier 
transport jets during ground turns are substantially less than those of 
smaller jet transports.'' Based on this rationale, for the A380 at 
maximum ramp weight--which is more than 30% heavier than any currently 
certificated airplane--the 0.5 g design turning load factor specified 
in Sec.  25.495 is conservative. A load factor of 0.45 g is more 
appropriate for the A380. The data provided to the FAA support this 
reduced factor.
    Therefore, in lieu of the requirements of Sec.  25.495, a special 
condition regarding ground turning loads is justified for the Model 
A380 airplane. The proposed special condition would require the 
applicant to determine the loads on the airplane during ground turning 
in a rational manner and would allow the applicant to determine a limit 
turning lateral load factor--not less than 0.45 g's--which is 
appropriate for the A380 at maximum ramp weight.

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.

[[Page 46108]]

    In lieu of the requirements of Sec.  25.495, the following special 
condition applies:
    a. The airplane is assumed to execute a steady turn by steering of 
any steerable gear or by application of any differential power. The 
airplane limit vertical load factor must be 1.0, and, in the absence of 
a more rational analysis, the limit airplane lateral load factor must 
be 0.5.
    b. The airplane is assumed to be in static balance, the lateral 
load factor being reacted by friction forces applied at the ground 
contact point of each tire. The lateral load must be shared between 
each individual tire in a rational or conservative manner. The 
distribution of the load on the tire must account at least for the 
effects of the factors specified in subparagraph c. (2) of this special 
condition.
    c. At maximum ramp weight, a limit value of lateral center of 
gravity (cg) inertia load factor lower than specified in subparagraph 
a. but not less than 0.45g (wing axis) may be used, if it can be shown 
by a rational analysis that this lower value cannot be exceeded. The 
rational analysis must consider at least the following:
    1. The maximum lateral load factor that can be reached during the 
full range of likely ground operations at maximum ramp weight, 
including ground turning, ``fishtailing,'' and high-speed runway exit. 
In each case, the full dynamic maneuver must be considered.
    2. The rational analysis must include at least the following 
parameters:
    (a) Landing gear spring curves and landing gear kinematics
    (b) Reliable tire friction characteristics
    (c) Airframe and landing gear flexibility when significant
    (d) Airplane rigid body motion
    (e) The worst combination of tire diameter, tire pressure, and 
runway shapes, specified in Sec. Sec.  25.511(b)(2), 25.511(b)(3), and 
25.511(b)(4).
    d. The limit lateral load factor at maximum landing weight is 0.5.
    e. Details of the analysis and any assumptions used must be agreed 
to by the FAA.
    Any assumptions made in the analysis must be based on the intrinsic 
characteristics of the airplane and must be independent of airfield 
geometry. Other influences that cannot be controlled by the airplane 
design must be conservatively assessed.

    Issued in Renton, Washington, on August 1, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-15655 Filed 8-8-05; 8:45 am]
BILLING CODE 4910-13-P