[Federal Register Volume 59, Number 19 (Friday, January 28, 1994)]
[Unknown Section]
[Page ]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-1465]
[Federal Register: January 28, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 93-NM-67-AD; Amendment 39-8805; AD 94-02-07]
Airworthiness Directives; McDonnell Douglas Model MD-11 Series
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain McDonnell Douglas Model MD-11 series airplanes,
that requires replacing the anti-skid control unit. This amendment is
prompted by three reports of failure of the center landing gear drag
link, after which the center landing gear swung aft and struck the
fuselage. The actions specified by this AD are intended to prevent
failure of the center landing gear drag link, which could result in
extensive damage to the fuselage structure.
DATES: Effective February 28, 1994. The incorporation by reference of
certain publications listed in the regulations is approved by the
Director of the Federal Register as of February 28, 1994.
ADDRESSES: The service information referenced in this AD may be
obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach,
California 90801-1771, Attention: Business Unit Manager, Technical
Publications--Technical Administrative Support, C1-L5B. This
information may be examined at the Federal Aviation Administration
(FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue,
SW., Renton, Washington; or at the FAA, Transport Airplane Directorate,
Los Angeles Aircraft Certification Office, 3229 East Spring Street,
Long Beach, California; or at the Office of the Federal Register, 800
North Capitol Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Andrew Gfrerer, Aerospace Engineer,
Systems and Equipment Branch, ANM-131L, FAA, Transport Airplane
Directorate, Los Angeles Aircraft Certification Office, 3229 East
Spring Street, Long Beach, California 90806-2425; telephone (310) 988-
5338; fax (310) 988-5210.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations to include an airworthiness directive (AD) that is
applicable to certain McDonnell Douglas Model MD-11 series airplanes
was published in the Federal Register on July 16, 1993 (58 FR 38321).
That action proposed to require replacing the anti-skid control unit.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter supports the proposal.
One commenter suggests that the proposed AD action is inappropriate
for two reasons:
1. Drag link failures occur only with the use of autobraking.
Therefore, if only manual brakes are used, there should be no
requirement to modify the anti-skid control unit.
2. Failure of the center landing gear drag link does not pose
sufficient risk to the airframe to warrant AD action.
The FAA does not concur with the commenter's suggestion that this
AD action is not warranted. As for the commenter's Item 1, the FAA
points out that there has been at least one case of failure of the
center gear with the application of manual brakes prior to touchdown of
the nose gear wheel. By replacing the Part Number (P/N) 6005304-1
control unit with the P/N 6005304-2 unit (as required by this AD),
center gear braking is inhibited both manually and through the use of
autobrakes until nose gear touchdown.
As for the commenter's Item 2, the FAA notes that there have been
at least three in-service failures of center landing gear drag links
that have caused significant structural damage to the airplane. In each
occurrence, the failed drag link allowed the center landing gear to
swing aft and strike the fuselage. Additionally, there are numerous
other possible scenarios involving similar failures that could result
in damage to the hydraulic and electrical systems of the airplane. The
center landing gear is also needed to properly distribute the
airplane's weight for heavy weight landings. For these reasons, the FAA
considers that failure of the center landing gear drag link does
present an unsafe condition sufficient to warrant mandated corrective
action. The appropriate vehicle for mandating such corrective action is
the airworthiness directive.
Two commenters request that the proposed compliance time of 9
months be extended to 12 months. The manufacturer has indicated that
the fleet of affected Model MD-11's could not be retrofitted within 9
months, given the current schedule of modifying the subject part on a
rotatable basis and the capacity of the manufacturer to modify the
control units. The FAA concurs with the commenter's request. Extending
the compliance time an additional 3 months will not adversely affect
safety and will allow the affected fleet to be modified in an orderly
manner, thereby minimizing the costs associated with special airplane
scheduling. Paragraph (a) of the final rule has been revised to specify
a compliance time of 12 months.
One commenter requests that the wording of references to the anti-
skid control unit be clarified. The preamble to the notice referred to
``the anti-skid control unit for the center landing gear;'' however,
this control unit controls all of the landing gears, not just the
center landing gear. The FAA agrees that clarification of this point is
needed and, where appropriate, has changed the wording in this final
rule accordingly.
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the changes previously
described. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
There are approximately 86 McDonnell Douglas Model MD-11 series
airplanes of the affected design in the worldwide fleet. The FAA
estimates that 32 airplanes of U.S. registry will be affected by this
AD, that it will take approximately 1 work hour per airplane to
accomplish the required actions, and that the average labor rate is $55
per work hour. Required parts will be provided by the manufacturer at
no cost to the operator. Based on these figures, the total cost impact
of the AD on U.S. operators is estimated to be $1,760, or $55 per
airplane. This total cost figure assumes that no operator has yet
accomplished the requirements of this AD.
The regulations adopted herein will 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 final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (1) Is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it may be obtained
from the Rules Docket at the location provided under the caption
ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends 14 CFR part
39 of the Federal Aviation Regulations 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:
94-02-07 McDonnell Douglas: Amendment 39-8805. Docket 93-NM-67-AD.
Applicability: Model MD-11 series airplanes, as listed in
McDonnell Douglas MD-11 Service Bulletin 32-30, dated March 3, 1993;
certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent potential failure of the center gear drag link, which
could lead to extensive damage to the fuselage structure, accomplish
the following:
(a) Within 12 months after the effective date of this AD,
replace the anti-skid control unit, part number 6005304-1, with a
new anti-skid control unit, part number 6005304-2, in accordance
with McDonnell Douglas MD-11 Service Bulletin 32-30, dated March 3,
1993.
(b) 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 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: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Los Angeles ACO.
(c) Special flight permits may be issued in accordance with FAR
21.197 and 21.199 to operate the airplane to a location where the
requirements of this AD can be accomplished.
(d) The replacement shall be done in accordance with McDonnell
Douglas MD-11 Service Bulletin 32-30, dated March 3, 1993. This
incorporation by reference was approved by the Director of the
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part
51. Copies may be obtained from McDonnell Douglas Corporation, P.O.
Box 1771, Long Beach, California 90801-1771, Attention: Business
Unit Manager, Technical Publications--Technical Administrative
Support, C1-L5B. Copies may be inspected at the FAA, Transport
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or
at the FAA, Transport Airplane Directorate, Los Angeles Aircraft
Certification Office, 3229 East Spring Street, Long Beach,
California; or at the Office of the Federal Register, 800 North
Capitol Street, NW., suite 700, Washington, DC.
(e) This amendment becomes effective on February 28, 1994.
Issued in Renton, Washington, on January 14, 1994.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 94-1465 Filed 1-27-94; 8:45 am]
BILLING CODE 4910-13-U
