Special Conditions: Airbus Model A380-800 Airplane, Extendable Length Escape System, 48451-48453 [E6-13780]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 71, Number 161 (Monday, August 21, 2006)]
[Rules and Regulations]
[Pages 48451-48453]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E6-13780]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM342; Special Condition No. 25-323-SC]


Special Conditions: Airbus Model A380-800 Airplane, Extendable 
Length Escape System

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 
extendable length escape slides. 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 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), 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, 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 Airbus Model A380-800 airplane has 16 emergency exits and 16 
escape slides to be used for evacuation of passengers in case of 
emergency. Of these, 14 are fixed-length escape slides, and two (at 
door M1) are extendable length escape slides. The extendable length 
escape slides have a 16-foot extension packed at the toe.
    Typically, airplanes have fixed length escape slides. However, it 
was not possible to use fixed length escape slides for the A380 door M1 
because of the extreme difference between normal sill height and high 
sill height associated with collapse of some of the

[[Page 48452]]

landing gear in an emergency. Some combinations of landing gear 
collapse could cause the airplane to tip back on its tail.
    On the door, there is an electronic sensor that evaluates the 
attitude of the airplane and determines whether the extension is 
needed. During normal operation, the extension remains packed at the 
toe end of the escape slide. When the extension is needed, the system 
sends a signal to a squib that allows the extension to be inflated 
during deployment. If the system detects that the slide extension has 
failed to deploy, a warning is activated that tells the flight 
attendants that the slide should not be used. The warning will also 
activate--if after initial deployment of the slide without the 
extension deploying--the attitude of the airplane changes to the extent 
that the extension should be deployed. The slide system design cannot 
accommodate deploying the extension after deployment of the main body 
of the slide.
    The performance requirements for escape systems are contained in 14 
CFR 25.810 and address several abnormal operating conditions as well as 
failure conditions and reliability. The requirements of Sec.  25.810 
remain applicable for the slide in the unextended mode, and for the 
most part, in the extended mode. The special conditions indicate where 
the requirements differ from the requirements of Sec.  25.810 for the 
slide in the extended mode.
    The extension is intended only for use at high sill heights. A 
typical fixed-length slide operating at high sill height does not 
satisfy all of the performance requirements of Sec.  25.810, but its 
variations in performance are understood and largely predictable. 
Certain performance criteria are valid regardless of sill height, 
whereas other aspects of performance can be expected to decline at 
higher sill heights. With an extendable slide, there is a step change 
in configuration and potentially a step change in performance.
    Therefore, special conditions are needed to ensure acceptable 
performance in the extended mode. Section 25.810 specifies the basic 
performance requirements for escape slides including wind testing, 
repeatability testing, and testing at adverse sill heights. Section 
25.1309(a) requires that systems perform under foreseeable operating 
conditions, such as extreme temperatures, and a demonstration that the 
system design is appropriate for its intended function. Standards for 
the equipment itself are contained in Technical Standard Order C69c and 
contribute to a satisfactory installation.
    Existing 14 CFR part 25 regulations governing the certification of 
the A380 do not adequately address certification requirements of an 
extendable length escape slide. The FAA is proposing special conditions 
to ensure that an extendable length escape slide performs adequately in 
both the unextended and the extended configuration.
    Technical Standard Order C69c addresses many detailed aspects of 
escape slide performance that are not specified in 14 CFR 25 but are 
generally considered essential to assuring adequate escape slide 
performance. These special conditions supplement the requirements of 14 
CFR 25, for the slide in its extended mode. However, because of the 
novel nature of this design, the special conditions will require that 
the escape slide receive TSO authorization or satisfy an equivalent 
standard.
    Wind tests are typically conducted only on fixed length slides at 
normal sill height. Since the regulations require that the 25 knot 
standard is met at the most critical wind angle, escape slides usually 
exceed 25 knots performance at other than the critical angle. The same 
is expected to be true of the slide in its extended mode, but some 
reduction in the required wind velocity is appropriate since the slide 
will be in an abnormal condition. Available data indicates that a value 
of 22 knots is appropriate to cover the slide in its extended mode at 
normal sill height. This corresponds to roughly 75% of the wind energy 
required for the slide in its normal attitude and will ensure that the 
slide can function in its extended mode at least as well as a fixed 
length slide under similar abnormal conditions.
    The special conditions also specify a rate for evacuation of 
passengers which is consistent with that of fixed length escape slides.

Discussion of Comments

    Notice of Proposed Special Conditions No. 25-06-03-SC, pertaining 
to the extendable length escape system for the Airbus A380 airplane, 
was published in the Federal Register on March 29, 2006. Comments were 
received from The Boeing Company and the Airline Pilots Association 
(ALPA).
    Requested change No. 1: ALPA states, ``The proposed language of * * 
* Special Condition [3] appears to address only one aspect of the 
current rule (wind velocity). The remaining elements of 
25.810(a)(1)(iv) should continue to apply.'' ALPA adds, ``Given that 
FAR part 25.810 provides that non-extendable slides have a 25 knot wind 
requirement at the most critical angle (with all gear extended), those 
same requirements must exist for the A380 extendable slide in its 
normal configuration or an equivalent wind requirement in its extended 
configuration.'' According to the commenter, ``* * * aircraft may be 
operated in winds greater than 25 knots, which suggests that a zone of 
risk remains unaddressed * * *. The special condition should intend to 
ensure the slide is able to perform the same point as required for 
other slides in service, which means that the slide and door sill 
should be configured as expected in actual service, and then the 25 
knot wind should be applied at the most critical angle.
    FAA response: The purpose of Special Condition 3 is to specify a 
reasonable criterion for the slide in an abnormal condition. There is 
no such criterion for typical fixed length escape slides, but they can 
be presumed to have less tolerance to wind when at adverse attitude 
than at normal attitude. Therefore, applying the same criterion to the 
slide in both the unextended and extended modes would be beyond what is 
done for a typical slide. The specific 22 knot criterion was arrived at 
empirically and is consistent with, if not beyond, the capabilities of 
a typical slide when at adverse attitude. Regarding the other aspects 
of Sec.  25.810(a)(1)(iv), see the FAA response to Requested change No. 
2.
    Requested change No. 2: The Boeing Company also comments on 
proposed Special Condition 3, suggesting that the text be changed to be 
similar to that in Sec.  25.810(a)(1)(iv).
    FAA response: The FAA agrees and has changed the wording to align 
more closely with the language of Sec.  25.810(a)(1)(iv).
    Requested change No. 3: ALPA points out that proposed Special 
Condition 5 specifies that a slide extension warning be available for 
ten minutes after the airplane comes to rest, but does not specify a 
minimum activation time for the warning. ALPA suggests that the special 
condition require that ``* * * the `slide extension' warning must be 
such that the cabin crew is immediately made aware of a non usable 
slide * * *.''
    FAA response: The FAA agrees and, accordingly, has changed the 
wording of Special Condition 5.
    Requested change No. 4: The Boeing Company comments on proposed 
Special Condition 2, as follows:
    ``The required evacuation rate of 45 persons per minute should be 
specified as the combined average rate of all test

[[Page 48453]]

runs to ensure that it will not be applied as a minimum threshold for 
each test run.
    FAA response: Special Condition 2 requires that Airbus demonstrate 
that the extendable length escape slide can achieve an evacuation rate 
of 45 persons per minute, but does not specify that any and every 
evacuation test must achieve that rate. Using the average of tests may 
be one way to demonstrate the specified rate, but it is not necessary 
to specify that as the only means.
    Requested change No. 5: Boeing further comments that proposed 
Special Condition 2 should specify that, ``with the exception of the 
sill height and the required average evacuation rate for this test 
series, all the other test conditions in Technical Standard Order TSC-
C69C, paragraph 5.4, (Basic Test Conditions), apply.''
    FAA response: This matter is addressed in Special Condition 1, 
which specifies that ``The extendable escape slide must receive TSO 
C69c authorization or the equivalent.''
    Except for the changes discussed above, 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.
    In addition to the provisions of 14 CFR part 25, the following 
special conditions apply:
    1. The extendable escape slide must receive TSO C69c authorization 
or the equivalent.
    2. In addition to the requirements of Sec.  25.810(a)(1)(iii) for 
usability in conditions of landing gear collapse, the deployed escape 
slide in the extended mode must demonstrate an evacuation rate of 45 
persons per minute per lane at the sill height corresponding to 
activation of the extension.
    3. In lieu of the requirements of Sec.  25.810(a)(1)(iv), the 
escape slide must be capable of being deployed in the extended mode, 
and with the assistance of one person, remain usable in 22 knot winds 
directed from the critical angle, with the airplane on all its landing 
gear.
    4. Pitch sensor tolerances and accuracy must be taken into account 
when demonstrating compliance with Sec.  25.1309(a) for the escape 
slide in both the extended and unextended modes.
    5. There must be a ``slide extension'' warning such that the cabin 
crew is immediately made aware of a non usable slide (i.e., the main 
slide has deployed and the door sill height is such that the extension 
should be deployed but cannot be deployed), even if this is due to the 
airplane attitude changing during the evacuation. The ability to 
provide such a warning must be available for ten minutes after the 
airplane is immobilized on the ground.

    Issued in Renton, Washington, on July 20, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-13780 Filed 8-18-06; 8:45 am]
BILLING CODE 4910-13-P