[Federal Register Volume 71, Number 175 (Monday, September 11, 2006)]
[Rules and Regulations]
[Pages 53316-53318]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-15010]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM320; Special Conditions No. 25-330-SC]


Special Conditions: Airbus Model A380-800 Airplane, Escape 
Systems Inflation Systems

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

[[Page 53317]]

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 escape 
system reliability. 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 August 28, 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 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 inflation system for the escape systems associated with the 
exits includes a pressurized cylinder with a mixture of carbon dioxide 
and argon in both gaseous and liquid states. The inflation system also 
includes a smaller cylinder containing a solid propellant that burns to 
generate gaseous propellant. The opening of the valve and the ignition 
of the propellant are accomplished by the firing of squibs. The firing 
of these squibs is sequenced to improve their performance in the 
extreme temperatures to which they are subjected. Firing of the squibs 
is controlled by a system mounted on the emergency exit.
    The proposed design for the escape systems on the A380 is much more 
complex than the design of systems currently in use. Typically, 
inflation systems for escape systems consist of a pressurized cylinder 
containing a mixture of gases and a regulator valve that reduces the 
outlet pressure supplied from the inflation cylinder. The regulator 
valve is opened either by mechanical means or by the firing of a squib.
    The regulations governing the certification of the A380 do not 
adequately address the certification requirements of this type of 
inflation system for an escape system. Furthermore, the Technical 
Standard Order (TSO) that addresses escape systems (i.e., TSO-C69c) 
does not adequately address this type of inflation system. The current 
requirements for escape system reliability are predicated on a simple 
inflation system, where reliability is driven by the performance of the 
inflatable itself. The existing requirements do not account for an 
inflation system that could adversely affect the overall reliability of 
the escape system.

[[Page 53318]]

    Since the A380 has 16 emergency exits, the requirements of Sec.  
25.810 require a total of 80 successful deployments (5 successive 
deployments for each exit). However, since the requirements apply to 
each system independently, failures in a system common to all the 
escape systems would not be adequately addressed. Therefore, the 
inflation system needs a specific requirement that will show adequate 
system reliability. With a goal of achieving 95% reliability of the 
inflation system with a 95% confidence, we are establishing such a 
requirement. As we noted above, the propellant used is designed to 
burn. The regulations do not address this type of propellant, and some 
measure of fire safety protection is needed. United Nations document 
No. ST/SG/AC.10/I1/Rev.3 ``Transport of Dangerous Goods, Manual of 
Tests and Criteria,'' section 13.7.1, contains a small scale test that 
addresses this concern. Propellants that pass this test will not be a 
fire hazard.
    Therefore, a special condition is needed to ensure that the 
inflation system for the A380 escape system is reliable and that the 
propellant itself does not constitute a fire hazard.

Discussion of Comments

    Notice of Proposed Special Conditions No. 25-05-15-SC, pertaining 
to escape systems inflation systems, was published in the Federal 
Register on August 9, 2005, (70 FR 46100). Comments were received from 
the Airline Pilots Association (ALPA) and an individual commenter.
    Requested change 1: ALPA recommends that the tests of the inflation 
system ``be conducted on the aircraft (or a mockup). Bench testing does 
not adequately ensure that the entire system will have the declared 
reliability. The system and its components should be subjected to 
accelerated aging representative of long-term storage (temperature and 
pressure cycling), long term exposure (high and low frequency 
vibration) as part of each test.'' ALPA adds that ``the inflation 
systems should be demonstrated to function in winds from the most 
severe angle at speeds up to at least the maximum wind speed (gust 
included) for which flight operations can occur.''
    FAA response: Many of these recommendations go beyond current 
regulatory requirements for inflation systems. For example, wind 
performance is already specified in 14 CFR part 25. The purpose of the 
special conditions is to establish criteria that will validate that the 
reliability of the inflation system as a component will not drive the 
overall reliability of the escape system. Thus tests on the escape 
slides installed on the airplane will be performed as is consistent 
with current practice, and additional tests will be performed on the 
inflation system itself. Accordingly, we have not changed the special 
conditions, as proposed.
    Requested change 2: An individual commenter expresses concern about 
various aspects of the inflation system, including its output of high 
temperature gas; residue from combustion of the solid propellant; high 
pressure produced in the inflation system; activation of the inflation 
system, including inadvertent activation by a lightning strike; and the 
need for a redundant manual (backup) power source for the inflation 
system.
    FAA response: These comments relate to the general safety and 
suitability of the inflation system for the escape system and its 
related components. These are fundamental considerations for any 
airplane system. Although the inflation system may warrant highly 
specific considerations, it is the need to show the reliability of the 
system relative to conventional design that makes it novel. Showing 
that the system elements are compatible with one another is a basic 
certification requirement for any system.
    To address the novel features of the inflation system requires 
imposition of special conditions in addition to the applicable 
requirements of Sec.  25.1301. The slide must be both soaked and 
inflated at a range of temperatures to determine its operating range. 
The minimum pressures are determined to establish evacuation rate and 
stiffness. Therefore, the initial internal pressure of the slide will 
not be an issue in the qualification. The electrical systems are 
protected against lightning by other requirements. The manual backup 
is, indeed, an alternative electrical supply, which is addressed in the 
system safety analysis. Accordingly, we have not changed the special 
conditions, 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.
    a. In addition to the requirements of Sec.  25.810, the following 
special condition applies:
    To ensure that the inflation system is a reliable design, it must 
be tested using 84 inflation/firing system bench tests with no more 
than one failure. For these special conditions, the inflation/firing 
system is defined as everything upstream of the outlet connection to 
the inflation valve, which includes but is not limited to the door-
mounted systems that provide the firing signals to the squibs, the 
squibs themselves, the solid propellant, and the valve.
    b. In addition to the requirements of Sec.  25.853(a) and Appendix 
F Part I (a)(ii), in standard atmosphere conditions, the following 
special condition applies:
    To ensure that the propellant itself does not contribute 
significantly to a fire, the propellant must be subjected to and must 
pass a standard ``Small-Scale Burning Test,'' as specified in United 
Nations document No. ST/SG/AC.10/11/Rev. 3 ``Transport of Dangerous 
Goods, Manual of Tests and Criteria,'' section 13.7.1.

    Issued in Renton, Washington, on August 28, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-15010 Filed 9-8-06; 8:45 am]
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