[Federal Register: August 21, 2006 (Volume 71, Number 161)]
[Rules and Regulations]
[Page 48451-48453]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr21au06-3]
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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
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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