[Federal Register Volume 60, Number 4 (Friday, January 6, 1995)]
[Proposed Rules]
[Pages 2041-2043]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-308]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-175-AD]
Airworthiness Directives; McDonnell Douglas Model MD-11 Series
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to certain McDonnell Douglas MD-11
series airplanes. This proposal would require the installation of an
electrically controlled slat system. This proposal is prompted by
numerous incidents of inadvertent deployment of the slats while the
airplane was in flight at cruise altitude. The actions specified by the
proposed AD are intended to prevent inadvertent deployment of the slats
during flight, which could result in an abrupt pitch up of the airplane
and consequent injury to crew and passengers; it could also result in
significant vibrations and cause damage to the elevators.
DATES: Comments must be received by March 3, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 94-NM-175-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except
Federal holidays.
The service information referenced in the proposed rule may be
obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach,
California 90801-1771, Attention: Business Unit Manager, Technical
Administrative Support, Dept. L51, M.C. 2-98. This information may be
examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue,
SW., Renton, Washington; or at the FAA, Los Angeles Aircraft
Certification Office, Transport Airplane Directorate, 3960 Paramount
Boulevard, Lakewood, California.
FOR FURTHER INFORMATION CONTACT: Wahib Mina, Aerospace Engineer,
Airframe Branch, ANM-120L, Los Angeles Aircraft Certification Office,
FAA, Transport Airplane Directorate, 3960 Paramount Boulevard,
Lakewood, California 90712-4137; telephone (310) 627-5324; fax (310)
627-5210.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed rule by submitting such written data, views, or arguments as
they may desire. Communications shall identify the Rules Docket number
and be submitted in triplicate to the address specified above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this notice may be changed in
light of the comments received.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed rule. All
comments submitted will be available, both before and after the closing
date for comments, in the Rules Docket for examination by interested
persons. A report summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 94-NM-175-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules
Docket No. 94-NM-175-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA previously has issued several AD's, applicable to McDonnell
Douglas Model MD-11 series airplanes, whose requirements have addressed
the problems associated with inadvertent deployment of the slats during
flight:
1. AD 92-13-03, amendment 39-8273 (57 FR 27155, June 18, 1992),
requires either modification or replacement of the flap control module
quadrant. That action was prompted by an incident in which a flightcrew
member inadvertently bumped the flap/slat handle, which then placed the
handle in an improper position that allowed the slats to extend during
cruise.
2. AD 92-14-51, amendment 39-8325 (57 FR 38264, August 24, 1992),
requires a one-time inspection of the slat mechanical input system for
proper clearance and rigging, and adjustment of the system, if
necessary. That action was prompted by two incidents in which the slats
extended during flight at cruise altitude because the rigging of the
slat input system was out of tolerance in three separate places in the
extended position
3. AD 92-26-03, amendment 39-8430 (57 FR 57906, December 8, 1992),
requires installing a cover on the flap/slat control module quadrant in
the flight compartment. That action was prompted by an incident in
which a flightcrew member inadvertently initiated slat deployment by
unintentionally depressing the zero degree detent gate while the flap/
slat handle was stowed in the retracted detent and the handle was not
in the proper position within the detent.
4. AD 93-15-03, amendment 39-8649 (58 FR 41421, August 4, 1993),
requires installing a retainer assembly on the upper pedestal flap/slat
control module quadrant in the flight compartment. That action was
prompted by several incidents in which flightcrew members accidentally
bumped the flap/slat handle and the slats deployed during cruise.
Deployment of the slats during flight at cruise altitude could
result in abrupt pitch up of the airplane and consequent injury to crew
and passengers; it could also create significant vibrations and cause
damage to the elevators.
In the preambles to those AD's, the FAA stated that the
requirements of each of the AD's were considered to be interim action
until final action was identified. The manufacturer had undertaken a
design review of the flap/slat system of the Model MD-11 in an effort
to positively address the problems associated with it, and the FAA
indicated that it would consider further rulemaking once that design
review was completed.
The manufacturer's design review has now been completed and the
manufacturer has developed an electrically controlled slat system.
Installation of this new system will reduce the possibility of
uncommanded operation of the slats and inadvertent displacement of the
flap/slat handle. The FAA has determined that the system positively
addresses the unsafe condition addressed in the previously-issued AD's.
In light of this, the FAA has determined that further rulemaking action
is indeed necessary, and this [[Page 2042]] proposed AD follows from
that determination.
The FAA has reviewed and approved McDonnell Douglas MD-11 Service
Bulletin 27-36, Revision 1, dated December 9, 1994, which describes
procedures for installation of the newly-designed electrically
controlled slat system. This system involves:
1. modifying and reidentifying the flap/slat module;
2. removing the slat control cables and associated pulleys,
pushrods, and spring coupler;
3. modifying the input bellcrank;
4. removing the inboard follow-up cable, drum, and pushrods to the
outboard valve;
5. removing the auto-slat actuator and pushrod;
6. replacing the mechanical slat control valves with electro-
mechanical slat control valves and installing associated wiring;
7. installing nameplates on the overhead circuit breaker panel;
8. installing circuit breakers and nameplates on the avionics
circuit breaker panel;
9. installing relays at the electrical and main avionics rack; and
10. installing lightplates on the pedestal.
Besides its main purpose to reduce the possibility of uncommanded
slat operation, other benefits of this new system include greatly
simplified flap/slat operation with reduced handle force, enhanced
protection against uncontained engine failure, and reduced aircraft
weight.
Since an unsafe condition has been identified that is likely to
exist or develop on other products of this same type design, the
proposed AD would require installation of an electrically controlled
slat system. The actions would be required to be accomplished in
accordance with the service bulletin described previously.
Installation of this new system necessarily entails removal of the
items that previously were required to be installed in accordance with
AD's 92-13-03, 92-14-51, 92-26-03, and 93-15-03. Therefore, once the
installation of the new system is completed on an airplane, the
requirements of the previously-issued AD's are considered terminated.
As a result of recent communications with the Air Transport
Association (ATA) of America, the FAA has learned that some operators
may misunderstand the legal effect of AD's on airplanes that are
identified in the applicability provision of the AD, but that have been
altered or repaired in the area addressed by the AD. The FAA points out
that all airplanes identified in the applicability provision of an AD
are legally subject to the AD. If an airplane has been altered or
repaired in the affected area in such a way as to affect compliance
with the AD, the owner or operator is required to obtain FAA approval
for an alternative method of compliance with the AD, in accordance with
the paragraph of each AD that provides for such approvals. A note has
been included to this notice to clarify this requirement.
There are approximately 124 Model MD-11 series airplanes of the
affected design in the worldwide fleet. The FAA estimates that 43
airplanes of U.S. registry would be affected by this proposed AD, that
it would take approximately 68 work hours per airplane to accomplish
the proposed actions, and that the average labor rate is $60 per work
hour. Required parts would be supplied by the manufacturer at no charge
to operators. Based on these figures, the total cost impact of the
proposed AD on U.S. operators is estimated to be $175,440, or $4,080
per airplane.
The total cost impact figure discussed above is based on
assumptions that no operator has yet accomplished any of the proposed
requirements of this AD action, and that no operator would accomplish
those actions in the future if this AD were not adopted.
The regulations proposed herein would not have substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government. Therefore, in
accordance with Executive Order 12612, it is determined that this
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the DOT
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
and (3) if promulgated, will not have a significant economic impact,
positive or negative, on a substantial number of small entities under
the criteria of the Regulatory Flexibility Act. A copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting the Rules
Docket at the location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
part 39 of the Federal Aviation Regulations (14 CFR part 39) as
follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
McDonnell Douglas: Docket 94-NM-175-AD.
Applicability: Model MD-11 series airplanes; as listed in
McDonnell Douglas MD-11 Service Bulletin 27-36, Revision 1, dated
December 9, 1994; certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must use the authority
provided in paragraph (c) to request approval from the FAA. This
approval may address either no action, if the current configuration
eliminates the unsafe condition; or different actions necessary to
address the unsafe condition described in this AD. Such a request
should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent inadvertent deployment of the slats during flight,
accomplish the following:
(a) Within 24 months after the effective date of this AD, modify
the airplane and install an electrically controlled slat control
system in accordance with McDonnell Douglas MD-11 Service Bulletin
27-36, Revision 1, dated December 9, 1994.
(b) Accomplishment of the actions required by paragraph (a) of
this AD constitutes terminating action for the requirements of the
following AD's:
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Amendment Federal Register
AD No. No. citation
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92-13-03............................... 39-8273 (57 FR 27155,
June 18, 1992).
92-14-51............................... 39-8325 (57 FR 38264,
Aug. 24, 1992).
[[Page 2043]]
92-26-03............................... 39-8430 (57 FR 57906,
Dec. 8, 1992).
93-15-03............................... 39-8649 (58 FR 41421,
Aug. 4, 1993).
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(c) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, Los Angeles Aircraft Certification
Office (ACO), FAA, Transport Airplane Directorate. Operators shall
submit their requests through an appropriate FAA Principal
Maintenance Inspector, who may add comments and then send it to the
Manager, Los Angeles ACO.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Los Angeles ACO.
(d) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where
the requirements of this AD can be accomplished.
Issued in Renton, Washington, on December 30, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-308 Filed 1-5-95; 8:45 am]
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