Special Conditions: Airbus Model A380-800 Airplane; Fire Protection, 74758-74761 [E6-21191]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 71, Number 239 (Wednesday, December 13, 2006)]
[Rules and Regulations]
[Pages 74758-74761]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E6-21191]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM313; Special Conditions No. 25-340-SC]


Special Conditions: Airbus Model A380-800 Airplane; Fire 
Protection

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, which has novel and unusual design features, such as a full-
length, double deck passenger cabin and electrical equipment bays 
distributed throughout the airplane. For these design features, the 
applicable airworthiness regulations do not contain adequate or 
appropriate safety standards regarding fire protection. 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 November 30, 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-

[[Page 74759]]

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 a subsequent letter 
(AI/L 810.0223/98 issue 3, dated January 7, 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 Airbus Model A380-800 airplane has novel or unusual design 
features relative to airplanes previously certificated under 14 CFR 
part 25. These design features include full-length passenger cabins on 
the main deck and the upper deck and electrical equipment bays that are 
distributed throughout the airplane--on the main deck and upper deck as 
well as in the lower lobe.
    Generally, transport category airplanes have one or two electrical 
equipment bays located in the lower lobe, adjacent to pressure 
regulator/outflow valves. If there were a fire in an electrical 
equipment bay, any smoke would be drawn toward the outflow valves and 
be discharged from the airplane without entering occupied areas. In the 
Airbus Model A380-800, the electrical equipment bays are distributed 
throughout the airplane. Only those equipment bays located in the lower 
lobe of the airplane are adjacent to pressure regulator/outflow valves.
    For this combination of electrical equipment bays distributed 
throughout the airplane and a double deck passenger cabin, the 
applicable airworthiness regulations do not contain adequate or 
appropriate safety standards regarding fire protection. Based upon its 
review of incidents of smoke in the passenger cabin, the FAA determined 
that an airplane with electrical equipment bays located below, on, and 
above the main deck of a double deck airplane presents a greater risk 
of smoke penetration than older designs with equipment bays only in the 
lower lobe adjacent to pressure regulator/outflow valves.
    In the event of a fire, airplanes with older designs rely upon 
``trial and error'' to determine whether the source of fire or smoke is 
in the electrical equipment bay. Typically, this involves the pilots 
following a procedure in the Airplane Flight Manual. It may involve 
shutting down power to the avionics equipment in one electrical 
equipment bay and reconfiguring the airplane's environmental control 
system (e.g., shutting down the recirculation fan) to see whether the 
amount of smoke in the flightdeck or passenger compartment is reduced 
or eliminated. If these actions do not eliminate the smoke, the flight 
crew may turn the power back on in the one electrical equipment bay, 
shut it off in the other equipment bay, and reconfigure the 
environmental control system again to see whether the smoke is now 
reduced or eliminated.
    This approach may be acceptable for airplanes with no more than two 
electrical equipment bays, both located in the lower lobe. In that 
case, there are only two options: a fire in an electrical equipment bay 
is in either one or the other. However, for an airplane with electrical 
equipment bays located below, on, and above decks, this approach is not 
sufficient, because--in the time it takes to determine the source of 
smoke--a fire could spread and the quantity of smoke could increase 
significantly.
    Furthermore, the ``trial and error'' approach raises concern over 
the lack of informational awareness that a flight crew would have 
should smoke penetration occur. Many factors--including the airflow 
pattern, configuration changes in the environmental control system, 
potential leak paths, and location of outflow/ regulator valves--would 
make it difficult to identify a smoke source, especially during flight 
or system transients, such as climbing/descending or changes in 
ventilation.
    Current regulations (Sec.  25.857) require that cargo compartments 
have a means to exclude hazardous quantities of smoke or fire 
extinguishing agent from penetrating into occupied areas of the 
airplane. However, there are no requirements that address the 
following:
     Preventing hazardous quantities of smoke or extinguishing 
agent originating from the electrical equipment bays from penetrating 
into occupied areas of the airplane;
     Installing smoke or fire detectors in electrical equipment 
bays; or
     Preventing hazardous quantities of smoke or extinguishing 
agent originating on one deck from spreading to the other deck.
    The FAA believes that smoke detectors are needed in all electrical 
equipment bays on the A380 to ensure that the flightcrew can make an 
informed decision as to the source of smoke and can shut down the 
specific electrical equipment bay from which the smoke is coming.

[[Page 74760]]

    These special conditions, therefore, require that there be a smoke 
or fire detection system in each electrical equipment bay. They also 
include requirements to prevent propagation of hazardous quantities of 
smoke or fire extinguishing agent between or throughout the passenger 
cabins on the main deck and the upper deck.

Discussion of Comments

    Notice of Proposed Special Conditions No. 25-05-08-SC, pertaining 
to fire protection for the Airbus A380 airplane, was published in the 
Federal Register on August 9, 2005 (70 FR 46108). A comment was 
received from the Boeing Company.
    Requested change 1: Boeing states that two conditions must be met 
in order to issue Special Conditions and that neither one is met in 
this case. Specifically, Boeing says that the distributed electrical 
equipment bays are not a novel or unusual design feature, because 
``There have been remote electrical equipment bays on many previously 
certificated airplane models, and similar Special Conditions have not 
been required.'' In addition, Boeing states that the current 
regulations are adequate to ensure that remote electrical equipment 
bays are safe. Boeing concludes, therefore, that the proposed Special 
Conditions are neither necessary nor justified.
    FAA response: The FAA does not agree. As stated above in the 
Discussion of Novel or Unusual Design Features, the FAA finds that both 
conditions required for issuance of a special condition are met: 
previous part 25 rulemaking did not envision distributed electrical 
equipment bays on passenger decks, and new standards are necessary to 
maintain the level of safety of part 25. The FAA requested that Boeing 
provide further corroboration of its comment that ``There have been 
remote electrical equipment bays on many previously certificated 
airplane models, and similar Special Conditions have not been 
required.'' Our review of the information provided by Boeing indicates 
that the specific design features incorporated into certain Boeing 
models are not the same as those on the Airbus A380. Specifically, the 
A380 has multiple electrical equipment bays distributed throughout the 
lower lobe and on and above the main deck, whereas Boeing airplanes 
have at most two electrical equipment bays, both located in the lower 
lobe.
    Historically, electrical equipment bays have been located in the 
lower lobe, adjacent to pressure regulator/outflow valves such that any 
smoke in the equipment bay would be drawn toward the outflow valves and 
leave the airplane without entering occupied areas. The presence of 
electrical equipment bays on and above the main deck presents a special 
challenge in the event of a fire and creates uncertainty as to whether 
smoke will penetrate into occupied areas of the airplane.
    To summarize, the FAA believes that it is appropriate to impose 
these special conditions for the A380-800 because:
    (1) The A380-800 is a large, double deck airplane with multiple 
electrical equipment bays distributed throughout, i.e., lower lobe, 
main deck, and upper deck.
    (2) The A380-800 has electrical equipment bays located above the 
lower lobe and not adjacent to pressure regulator/outflow valves.
    (3) The A380-800 has more than two electrical equipment bays.
    (4) The A380-800 has electrical equipment bays located on or above 
passenger decks or the flight deck.
    (5) An airplane with this combination of electrical equipment bays 
and passenger decks presents a greater risk of smoke penetration than 
older designs with equipment bays only in the lower lobe, adjacent to 
pressure regulator/outflow valves.
    (6) For this combination of design features, the applicable 
airworthiness regulations do not contain adequate or appropriate safety 
standards regarding fire protection.
    (7) All electrical equipment bays on the A380 should contain smoke 
or fire detectors to ensure that in the event of a fire in one 
equipment bay the flight crew has sufficient situational information to 
enable them to shut down the correct electrical equipment bay.
    Requested change 2: Boeing objects to applying the proposed Special 
Conditions ``to all [electrical] equipment bays, not just the remote 
equipment bay(s) that the FAA has determined to be novel and 
inadequately covered by the existing regulations. Applying this Special 
Condition to the main equipment bay appears to be a form of general 
rulemaking via Special Condition.''
    FAA response: The FAA does not agree. We contacted the Boeing 
Company regarding its comment and asked for clarification. It appears 
that Boeing's comment was focused on multiple electrical equipment bays 
located in the lower lobe and not the distributed electrical equipment 
bays in the A380 design. However, it is not only the remote electrical 
equipment bays which are a novel or unusual design feature. It is the 
combination of electrical equipment bays distributed on the main deck, 
the upper deck, and the lower lobe along with full-length passenger 
cabins on the main deck and the upper deck. This combination raises the 
possibility that smoke from a fire in an electrical equipment bay will 
penetrate into the flightdeck or into one or both passenger cabins. As 
noted above, the presence of smoke detectors in these equipment bays 
will ensure that the flight crew has sufficient situational information 
to enable them to shut down the correct electrical equipment bay and to 
prevent hazardous quantities of smoke from entering the flight deck or 
passenger cabins.
    Based on the fact that the electrical distribution center on the 
A380 includes electrical equipment bays in locations where fire and 
smoke are more hazardous to passengers, we believe that this special 
condition should apply not only to electrical equipment bays on the 
passenger decks, but to all electrical equipment bays. To do otherwise 
would not protect the entire electrical distribution system when such 
protection could be accomplished readily.
    Requested change 3: Finally, Boeing comments that the proposed 
Special Conditions add requirements for detecting smoke and fire and 
for preventing penetration of smoke and that such requirements have 
previously been associated with fire protection for cargo compartments, 
but not for electrical equipment bays. According to the commenter,

    There have been many issues raised with the smoke quantities and 
test methods for these tests, especially for cargo compartment 
tests. None of these discussions have included equipment bays as the 
location of the test, or the materials in the equipment bay as the 
fuel of the fire. Therefore, there is no agreement as to the 
detailed test procedures for the proposed equipment bay detection 
tests.

    FAA response: This comment pertains to how Airbus will show 
compliance with the requirements to install a smoke or fire detection 
system in each electrical equipment bay and to prevent smoke 
originating from the electrical equipment bays from penetrating between 
or throughout passenger cabins on the main deck and the upper deck. We 
have discussed these issues with Airbus and with specialists within the 
European Aviation Safety Agency and have established appropriate test 
criteria through the issue paper process.

Clarification

    The FAA has revised the text in the Discussion of Novel or Unusual 
Design Features to clarify that the special conditions apply to 
propagation of

[[Page 74761]]

smoke or extinguishing agents between or throughout the main deck and 
upper deck passenger cabins. Similarly, we have revised the text of 
Special Condition a.2.(c) to clarify that smoke from a source below the 
main deck must not rise above armrest height on the main deck.

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. Requirements to prevent propagation of smoke or extinguishing 
agents between or throughout main deck and upper deck passenger cabins:
    1. To prevent such propagation, the following must be demonstrated:
    (a) Means to prevent hazardous quantities of smoke or extinguishing 
agent originating from the electrical equipment bays from 
incapacitating passengers and crew, and
    (b) Means to prevent hazardous quantities of smoke or extinguishing 
agent originating from one deck from propagating to the other deck via 
vents, stairways, and joints in the floor/ceiling.
    2. A ``small quantity'' of smoke may enter an occupied area only 
under the following conditions:
    (a) The smoke enters occupied areas during system transients \1\ 
from below deck sources. No sustained smoke penetration beyond that 
from environmental control system transients is permitted.
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    \1\ Transient airflow conditions may cause air pressure 
differences between compartments, before the ventilation and 
pressurization system is reconfigured. Additional transients occur 
during changes to system configurations such as pack shut-down, fan 
shut-down, or changes in cabin altitude; transition in bleed source 
change, such as from intermediate stage to high stage bleed air; and 
cabin pressurization ``fly-through'' during descent may reduce air 
conditioning inflow. Similarly, in the event of a fire, a small 
quantity of smoke that penetrates into an occupied area before the 
ventilation system is reconfigured would be acceptable under certain 
conditions described within this special condition.
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    (b) Penetration of the small quantity of smoke is a dynamic event, 
involving either dissipation or mobility. Dissipation is rapid dilution 
of the smoke by ventilation air, and mobility is rapid movement of the 
smoke into and out of the occupied area. In no case, should there be 
formation of a light haze indicative of stagnant airflow, as this would 
indicate that the ventilation system is failing to meet the 
requirements of Sec.  25.831(b).
    (c) The smoke from a smoke source below the main deck must not rise 
above armrest height on the main deck.
    (d) The smoke from a source on the same deck or above the deck must 
dissipate rapidly via dilution with fresh air and be evacuated from the 
airplane. A procedure must be included in the Airplane Flight Manual to 
evacuate smoke from the occupied areas of the airplane. In order to 
demonstrate that the quantity of smoke is small, a flight test must be 
conducted which simulates the emergency procedures used in the event of 
a fire during flight, including the use of Vmo/
Mmo descent profiles and a simulated landing, if such 
conditions are specified in the emergency procedure.
    b. Requirement for fire detection in electrical equipment bays:
    A smoke or fire detection system that complies with 14 CFR 
25.858(c) and (d) must be provided for each electrical equipment bay. 
Each system must provide a visual indication to the flight deck within 
one minute after the start of a fire in an electrical equipment bay. 
Airplane tests must be conducted to show compliance with this 
requirement, and the performance of the smoke or fire detection system 
must be shown, in accordance with Advisory Circular 25-9A or by other 
means acceptable to the FAA.

    Issued in Renton, Washington, on November 30, 2006.
Kevin Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-21191 Filed 12-12-06; 8:45 am]
BILLING CODE 4910-13-P