[Federal Register: August 21, 2006 (Volume 71, Number 161)]
[Rules and Regulations]
[Page 48449-48451]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr21au06-2]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM343; Special Conditions No. 25-322-SC]
Special Conditions: Airbus Model A380-800 Airplane, Airplane
Jacking Loads
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 airplane
jacking loads. 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.
DATES: Effective Date: The effective date of these special conditions
is July 20, 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
[[Page 48450]]
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 had been moved from May 2005, to January 2006, to match the
delivery date of the first production airplane. In a subsequent letter
(AI/L 810.0223/98 issue 3, dated January 27, 2006), Airbus stated that
its target date for type certification is October 2, 2006. In
accordance with 14 CFR 21.17(d)(2), Airbus chose a new application date
of December 20, 1999, and requested that the 7-year certification
period which had already been approved be continued. The FAA has
reviewed the part 25 certification basis for the Model A380-800
airplane, and no changes are required based on 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
The A380 has a multi-leg landing gear arrangement consisting of a
nose gear, two wing mounted gear, and two body mounted gear. This
arrangement is different from the simpler, conventional landing gear
arrangement envisioned by the jacking load requirements of 14 CFR
25.519. Those regulations assume a landing gear arrangement comprising
a three point suspension system (two main gear and a nose or tail gear)
in which load sharing between the landing gear can be determined
without considering the flexibility of the airframe.
For a five point suspension system, like that of the A380,
calculations that consider airplane flexibilities are necessary to
determine load sharing between landing gear units accurately. (The
flexibility of the individual landing gear oleos and of the airplane
itself affect how the weight of the airplane is distributed among the
individual landing gear units.)
Special conditions are necessary to allow a rational analysis of
the jacking condition for the main and body landing gear. (This
analysis will include the case of bogie gears where one leg of a bogie
is jacked and the other leg is supported on a tripod--which is not
addressed by Sec. 25.519.) The applicant has proposed a rational
jacking analysis, which makes reasonable or conservative assumptions
about the runway configuration and ground wind speeds.
Discussion of Comments
Notice of Proposed Special Conditions No. 25-06-04-SC, pertaining
to airplane jacking loads for the Airbus A380 airplane, was published
in the Federal Register on March 28, 2006. A single comment which
supports the intent and language of the special conditions, as
proposed, was received from the Airline Pilots Association (ALPA).
Accordingly, the special conditions are adopted 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 following special conditions are issued as part of
the type certification basis for the Airbus A380-800 airplane.
Part I
In lieu of compliance with 14 CFR 25.519(b)(1), for jacking by the
landing gear at the maximum ramp weight of the airplane, the airplane
structure may be designed to withstand the maximum limit loads arising
from conditions a. and b. below.
a. The loads arising from jacking by the landing gear may be
derived from a rational analysis under both of the following
conditions:
1. A ramp crown defined by a 1.5% gradient, the crest of the
gradient to be in the most adverse position for the loading of the
undercarriage unit in question; and the maximum allowable steady wind
for jacking operations from any horizontal direction; and the most
adverse combination of oleo leg pressures within service tolerances;
and jack(s) at the maximum possible overshoot.
2. A ramp crown defined by a 1.5% gradient, the crest of the
gradient to be in the most adverse position for the loading of the
undercarriage unit in question; and twice the maximum allowable steady
wind for jacking operations from any horizontal direction; and a
nominal distribution of oleo leg pressures; and jacking performed in
accordance with recommended procedures.
b. The limit horizontal load at the jacking point undercarriage
unit may not be less than the higher of that derived from the above
rational analysis or 0.33 times the limit static vertical
[[Page 48451]]
reaction found with the undercarriage unit in question supported at the
jacking points with the aircraft in the unjacked position. This load
must be applied in combination with the vertical loads arising from the
analysis of (a) above.
Part II
Jacking equipment used for the airplane jacking operation must be
controlled by a specification that assures that jacking operations are
conducted in a manner that is consistent with the provisions of this
special condition. Jacking instructions must be developed and
incorporated in the Instructions for Continued Airworthiness to assure
that the proper jacking equipment is used and that the jacking
operation is conducted in a manner consistent with the provisions of
this special conditions. The jacking instructions may be by means of
placards conspicuously located near the jacking points or by other
suitable means acceptable to the Administrator.
Issued in Renton, Washington, on July 20, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E6-13789 Filed 8-18-06; 8:45 am]
BILLING CODE 4910-13-P