[Federal Register: September 11, 2006 (Volume 71, Number 175)]
[Rules and Regulations]
[Page 53310-53313]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr11se06-4]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM314; Special Conditions No. 25-326-SC]
Special Conditions: Airbus Model A380-800 Airplane; Stairways
Between Decks
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
stairways between decks. 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.
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
[[Page 53311]]
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 incorporates seating on two full-length passenger decks,
each of which has the capacity of a typical wide body airplane. Two
staircases--one located in the front of the cabin and one located in
the rear--allow for the movement of persons between decks. With large
seating capacities on the main deck and the upper deck of the A380-800
airplane, the staircases need to be able to support movement between
decks in an inflight emergency. In addition, although compliance with
the evacuation demonstration requirements of Sec. 25.803 does not
depend on the use of stairs, there must be a way for passengers on one
deck to move to the other deck during an emergency evacuation. This
need must be addressed in the certification of the airplane.
The regulations governing the certification of the A380 do not
adequately address a passenger airplane with two separate full-length
decks for passengers. The Boeing 747 and Lockheed L-1011 airplanes were
certificated with limited seating capacity on two separate decks, and
special conditions were issued to certificate those arrangements. When
the seating capacity of the upper deck of the Boeing 747 exceeded 24
passengers, the FAA issued Special Conditions 25-61-NW-1 for a maximum
seating capacity of 32 passengers on the upper deck for take-off and
landing. A second set of Special Conditions, 25-71-NW-3, was issued to
cover airplanes with a maximum seating capacity of 45 passengers on the
upper deck for take-off and landing. That second set of Special
Conditions was later modified to address airplanes with a maximum
seating capacity of 110 passengers on the upper deck. These previously
issued special conditions provided a starting point for the development
of special conditions for the A380-800 airplane.
In the case of both the L-1011 and the 747, the special conditions
were based on the requirements and associated level of safety in place
at the time of application for type certificate. The requirements and
the level of safety have improved significantly since that time, and
these special conditions reflect those improvements.
In addition to the requirements of Sec. Sec. 25.803 and 25.811
through 25.813, special conditions are needed to address the movement
of passengers between the two full-length decks on the Model A380.
These special conditions provide additional requirements for the
stairways to ensure the safe passage of occupants between decks during
moderate turbulence, an inflight emergency, or an emergency evacuation.
Discussion of Comments
Notice of Proposed Special Conditions No. 25-05-09, pertaining to
stairways between decks, was published in the Federal Register on
August 9, 2005 (70 FR 46110). Comments were received from the Boeing
Company, the Airline Pilots Association (ALPA), and the Association of
Flight Attendants (AFA).
Requested change 1: The Boeing Company states that as a general
matter ``a single stairway has been shown through service history of
the Boeing Model 747-300 and -400 to be sufficient for an upper deck
that is approved for up to 110 passengers (or has a single pair of type
A exits). By comparison, the FAA is requiring a minimum of two
stairways for the Model A380-800, which has three pairs of upper deck
type A exits (or is theoretically eligible for up to 330 passengers on
the upper deck).'' The commenter recommends that the special conditions
state that one stairway is sufficient for an upper deck that is
approved to carry no more than 110 passengers.
FAA response: The special conditions pertain to the design of the
Model A380-800; thus discussion of designs that require only one
stairway is not relevant.
Requested change 2: ALPA requests that a special condition be added
to ensure that the stairway can be used when the aircraft fuselage
suffers minor deformation during a survivable accident or incident.
FAA response: The stairway design must comply with all structural
requirements; therefore, no change has been made to the special
conditions, as proposed.
Requested change 3: In terms of Special Condition a., ALPA suggests
the following:
``The procedures developed to accommodate the carriage of an
incapacitated person from one deck to the other should be demonstrated
using personnel from air carrier crews,
[[Page 53312]]
representing the largest and smallest persons that the carriers may
employ and with the same level of training that will be provided in
service.''
FAA response: The FAA does not believe that this is necessary. The
design of the stairway must be demonstrated to be suitable for
evacuation of an incapacitated person, and this might be accomplished
by either crew or passengers assisting the crew. The intent of this
requirement is to ensure that one of the stairs provide a means to
transport an incapacitated person from the upper deck, in much the way
such a person would be evacuated along the aisle of a single deck
airplane. Any crew duties necessary to facilitate the evacuation should
be consistent with existing processes and not require extraordinary
effort. The comment is related more to the means of demonstrating
compliance with the requirement than the substance of the requirement
itself. Therefore, we have not changed the special condition, as
proposed.
Requested change 4: The Boeing Company requests that Special
Condition b. be revised to read as follows:
``There must be at least two stairways between decks that meet the
following requirements:
``The stairways must be designed * * * One of these stairways must
be the stairway specified in paragraph a. above.''
FAA response: The suggested wording is more explicit than that
proposed, and we have changed the wording of Special Condition b.
accordingly.
Requested change 5: Regarding Special Condition c.1., AFA seeks
clarification of the types of assistance needed by cabin crew in regard
to merging of passengers from the two decks into the stairways. The
commenter adds that, ``Analysis is not an acceptable tool for
demonstrating these requirements [for each stairway between decks].''
FAA response: The assistance provided would be consistent with that
currently provided by flight attendants to facilitate evacuation. In
terms of the method of demonstration used to substantiate that the
requirements are met, testing is more likely but analysis could be an
appropriate method. Accordingly, no change has been made to the special
conditions, as proposed.
Requested change 6: Both the Boeing Company and AFA suggest
revising Special Condition c.2. to require a handrail on both sides of
a stairway, if the stairway is wide enough to accommodate more than a
single lane of persons. AFA also suggests that there be a special
condition relative to limit loads on the handrails.
FAA response: The current design provides two handrails. The FAA
does not consider it necessary to require two handrails, although other
performance requirements in this special condition for the stairs may
dictate the need for two handrails.
The proposed special conditions require that the handrail design
address foreseeable operating conditions, including turbulence and
adverse attitude. This will necessitate a structural design capable of
performing its function under those conditions. Stating the requirement
objectively rather than prescriptively permits more flexibility in the
design and takes the specific installation into account. In fact,
Airbus has used the design specifications from other industries in the
design of the stairs; in practice, therefore, those strength criteria
will form the baseline for the design.
Requested change 7: The Boeing Company suggests revising Special
Condition c.4. to address narrow stairways with handrails on both
sides, because such a stairway ``can be used safely in the conditions
specified without requiring a wall above the handrail or equivalent on
each side.''
FAA response: The special condition permits an equivalent means, so
that--if the use of a handrail were shown to be equivalent in certain
cases--the special condition would permit its use.
Requested change 8: AFA supports Special Condition c.5. and
suggests that there should also be special conditions ``requiring that
the surface of the treads and landings should also be designed to
include adequate slip resistant properties. Additionally, the treads
and risers should have uniform dimensions in order to allow the user to
establish a uniform gait when using the stairway.''
FAA response: The regulations already address slip resistance for
surfaces likely to become wet in service, so this aspect is not novel.
In terms of the detailed design of the treads and risers, rather than
being prescriptive, we are using a performance based approach in the
special condition. Performance-based requirements will very likely
drive the design, as suggested, since the suggested features are
generally regarded as necessary to achieve efficient and safe stair
usage.
Requested change 9: Although acknowledging that the proposed
illumination level is the same as for the rest of the airplane
interior, ALPA states that the proposed level of illumination for the
stairway is far too low. The commenter recommends that the illumination
should be an average of 1 foot-candle with a minimum of 0.1 foot-
candle. This is the same as that specified in the NFPA Life Safety
Code, 1997.
FAA response: As noted by ALPA, the emergency lighting level is
consistent with the other requirements for emergency lighting in the
cabin as well as for stairs on other airplanes. The general emergency
lighting requirements concerning battery discharge and cold-soak will
also apply to the lighting on the stairs, so the typical illumination
values will, in fact, be much higher. The proposed standards have
demonstrated satisfactory service experience. Therefore, we have made
no change to the special condition, as proposed.
Requested change 10: The Boeing Company suggests revising Special
Condition c.8. to read as follows:
``An exit sign must be provided in the upper deck near the
stairway, visible to upper deck passengers while seated or standing. In
addition, the upper end of the stairway must include an exit sign
visible to passengers while descending the stairway, leading them to
main deck exits beyond the sign. Both exit signs must meet the
requirements of Sec. 25.812(b)(1)(ii).'' The commenter further
recommends that--if a lower exit sign is required in the stairway--the
sign should not be visible to main deck passengers who are not on the
stairs.
FAA response: As proposed, Special Condition c.8. specifies that an
exit sign be visible to a person on the stairway. This will provide
guidance to people using the stairway, but not necessarily direct
people to the stairway. The optimum evacuation strategy is for people
to evacuate from the deck on which they are seated. Adding signs to
direct people to the stairs could actually slow the overall evacuation.
Conversely, if people do use the stairs, they will have an indication
that exits are available. Therefore, we have not changed the text of
the Special Conditions, as proposed.
Requested change 11: The Boeing Company suggests that Special
Condition d. be revised to read, ``Each entrance or path to the
entrance of a stairway must be visible from a seat designated for
flight attendants' use during taxi, takeoff, and landing. Cabin crew
procedures and positions must be established. * * *''
A comment submitted by AFA states, ``AFA agrees that cabin crew
positions and procedures need to be established to help manage the use
of the stairs between decks but do not believe that cabin crew can
``control'' or prevent movement of * * * passengers between the two
decks.'' The commenter
[[Page 53313]]
suggests replacing the word ``control'' with the word ``manage'' [or
``management''] to reflect a more realistic situation.
FAA response: The direct view requirements will be applied to the
stairs as they are to other egress paths. The FAA agrees that
``manage'' is a better term than ``control'' and has changed the text
of Special Condition d. accordingly.
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 requirements of Sec. Sec. 25.803 and 25.811
through 25.813, the following special conditions apply:
a. At least one stairway between decks must meet the following
requirements:
The stairway accommodates the carriage of an incapacitated person
from one deck to the other. The crew member procedures for such
carriage must be established.
b. There must be at least two stairways between decks that meet the
following requirements: The stairways must be designed such that
evacuees can achieve an adequate rate for going down or going up under
probable emergency conditions, including a condition in which a person
falls or is incapacitated while on a stairway. One of the stairways
must be the stairway specified in paragraph a. above.
c. Each stairway between decks must meet the following
requirements:
1. It must have an entrance, exit, and gradient characteristics
that--with the assistance of a crew member--would allow the passengers
of one deck to merge with passengers of the other deck during an
evacuation and exit the airplane. These entrance, exit, and gradient
characteristics must occur with the airplane in level attitude and in
each attitude resulting from the collapse of any one or more legs of
the landing gear. These requirements must be demonstrated by tests and/
or analysis.
2. The stairway must have a handrail on at least one side in order
to allow people to steady themselves during foreseeable conditions,
including but not limited to the condition of gear collapse on the
ground and moderate turbulence in flight. The handrails must be
constructed, so that there will be no obstruction on them which will
cause the user to release his/her grip on the handrail or will hinder
the continuous movement of the hands along the handrail. Handrails must
be terminated in a manner which will not obstruct pedestrian travel or
create a hazard. Adequacy of the design must be demonstrated by using
persons representative of the 5% female and the 95% male.
3. The stairway must be designed and located to minimize damage to
it during an emergency landing or ditching.
4. The stairway must have a wall or the equivalent on each side to
minimize the risk of falling and to facilitate use of the stairway
under conditions of abnormal airplane attitude.
5. Treads and landings must be designed and demonstrated to be free
of hazard. The landing area at each deck level must be demonstrated to
be adequate in terms of flow rate for the maximum number of people that
will be using the stair in an emergency. Treads and risers must be
designed to ensure an easy and safe use of the stairway.
6. General emergency illumination must be provided so that--when
measured along the centerlines of each tread and landing--the
illumination is not less than 0.05 foot-candle.
7. In normal operation, the general illumination level must not be
less than 0.05 foot-candles. The assessment must be done under day
light and dark of night conditions.
8. Both stairway ends must be indicated by an exit sign visible to
passengers when in the stairway. This exit sign must meet the
requirements of Sec. 25.812(b)(1)(ii).
9. A floor proximity path marking system which meets the
requirements of Sec. 25.812(e) must be available to guide passengers
in the stairway to the stairway ends. It must not direct the occupants
of the cabin to the stair entrance.
10. The public address system must be audible in the stairway
during all flight phases.
11. ``No smoking'' and ``return to seat'' signs must be installed
and must be visible in the stairway both going up and down and at the
stairway entrances.
d. Cabin crew procedures and positions must be established to
manage the use of the stairs on the ground and in flight under both
normal and emergency situations. This may require that cabin crew
members have specific dedicated duties for the management of the stairs
during emergency and precautionary evacuations.
e. It should not be hazardous for crew members or passengers who
are returning to their seats to use the stairways during moderate
turbulence.
Issued in Renton, Washington, on August 28, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E6-15001 Filed 9-8-06; 8:45 am]
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