[Federal Register Volume 61, Number 18 (Friday, January 26, 1996)]
[Rules and Regulations]
[Pages 2407-2409]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-475]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-91-AD; Amendment 39-9485; AD 96-01-09]
Airworthiness Directives; McDonnell Douglas Model DC-9-80 Series
Airplanes and Model MD-88 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 DC-9-80 series airplanes
and Model MD-88 airplanes, that requires installation of hydraulic line
restrictors in the main landing gear (MLG), and modification of the
hydraulic damper assembly of the MLG. This amendment is prompted by
reports of vibration occurring in the MLG during landing; in some
cases, such vibration has led to the collapse of the MLG. The actions
specified by this AD are intended to prevent incidents of vibration in
the MLG, which can adversely affect the integrity of the MLG.
DATES: Effective February 26, 1996.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of February 26, 1996.
ADDRESSES: The service information referenced in this AD may be
obtained from McDonnell Douglas Corporation, 3855 Lakewood Boulevard,
Long Beach, California 90846, Attention: Technical Publications
Business Administration, Department C1-L51 (2-60). 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, Los Angeles Aircraft Certification Office,
Transport Airplane Directorate, 3960 Paramount Boulevard, Lakewood,
California; or at the Office of the Federal Register, 800 North Capitol
Street NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Walter Eierman, Aerospace Engineer,
Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft
Certification Office, 3960 Paramount Boulevard, Lakewood, California
90712; telephone (310) 627-5336; fax (310) 627-5210.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to certain McDonnell Douglas Model
DC-9-80 series airplanes and Model MD-88 airplanes was published in the
Federal Register on September 26, 1995 (60 FR 49523). That action
proposed to require installation of hydraulic line restrictors in the
main landing gear (MLG), and modification of the hydraulic damper
assembly of the MLG.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Four commenters support the proposal.
One commenter requests that the FAA revise the proposal to include
references to later revisions of the pertinent service bulletins, which
were recently released. The FAA concurs. Subsequent to the issuance of
the proposal, the FAA reviewed and approved Revision 1 of McDonnell
Douglas MD-80 Service Bulletin MD80-32-276, dated October 17, 1995; and
Revision 1 of McDonnell Douglas MD-80 Service Bulletin MD80-32-278,
dated September 6, 1995. These revisions are essentially identical to
the original issues of the service bulletins (which were referenced in
the proposal), but contain additional clarifying information.
Additionally, the FAA has reviewed and approved McDonnell Douglas MD-80
Alert Service Bulletin MD80-A32-286, dated September 11, 1995, which
contains, among other things, instructions for installing filtered
restrictors in the MLG hydraulic brake system. The FAA has revised the
final rule to include these newly released service bulletins as
additional sources of appropriate service instructions.
One commenter requests that paragraph (a) of the proposal be
revised to extend the compliance time for installation of the brake
line restrictors. This commenter is concerned that an ample number of
required parts will not be available to modify its large fleet within
the proposed compliance time of 9 months. The FAA does not concur that
an extension of the compliance time is necessary. In McDonnell Douglas
MD-80 Service Bulletin MD80-32-276, the manufacturer recommended that
the installation of the restrictors be accomplished on the affected
fleet within 12 months. Since the latest revision of that service
bulletin was issued on October 17, 1995, the FAA considers it to be
substantiation that the manufacturer can support parts production and
delivery for the affected fleet through October 17, 1996. Since
compliance with this AD is required by approximately that same date,
the FAA does not foresee that the availability of required parts will
be a problem for operators. However, under the provisions of paragraph
(c) of the final rule, the FAA may approve requests for adjustments to
the compliance time if data are submitted to substantiate that such an
adjustment would provide an acceptable level of safety.
One commenter requests that the FAA defer action on the proposed
requirements of paragraph (b), which would require operators to modify
the hydraulic damper assembly. This commenter contends that further
research and testing of the structural integrity of the reservoir
should be accomplished first to substantiate that the installation of
the hydraulic brake line restrictors [that would be required by
paragraph (a) of the proposal] will successfully curb the vibration
problems. This commenter claims that, if the most vulnerable part of
the damper design is the reservoir, then no amount of ``efficiency
improvements'' to the basic damper assembly will help.
[[Page 2408]]
The FAA does not concur with the commenter's request. The FAA finds
that the previous evaluations of this problem confirm that the
reservoir failures are the result of the landing gear vibration, and
are not a preceding failure that contributes to the vibration. Based on
these evaluations and other data obtained to date, the FAA maintains
that the modification required by paragraph (b) is both warranted and
appropriate.
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 1,100 Model DC-9-80 series airplanes and
Model MD-88 airplanes of the affected design in the worldwide fleet.
The FAA estimates that 600 airplanes of U.S. registry will be affected
by this proposed AD.
Accomplishment of the installation of the brake line restrictor, as
described in McDonnell Douglas MD-80 Service Bulletin MD80-32-276, will
take approximately 4 work hours per airplane to accomplish, at an
average labor rate of $60 per work hour. Required parts will cost
approximately $928 per airplane. Based on these figures, the cost
impact of this installation on U.S. operators is estimated to be
$700,800, or $1,168 per airplane.
Accomplishment of the modification of the hydraulic damper
assembly, as described in McDonnell Douglas MD-80 Service Bulletin
MD80-32-278, will take approximately 6 work hours per airplane to
accomplish, at an average labor rate of $60 per work hour. Required
parts will cost approximately $4,000 per airplane. Based on these
figures, the cost impact of this modification on U.S. operators is
estimated to be $2,616,000, or $4,360 per airplane.
Based on the figures discussed above, the FAA estimates that the
cost impact of this AD on U.S. operators would be approximately
$3,316,800, or $5,528 per airplane. This cost impact figure is based on
assumptions that no operator has yet accomplished any of the
requirements of this AD action, and that no operator would accomplish
those actions in the future if this AD were not adopted.
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 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 USC 106(g), 40101, 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
96-01-09 McDonnell Douglas: Amendment 39-9485. Docket 95-NM-91-AD.
Applicability: Model DC-9-81 (MD-81), -82 (MD-82), -83 (MD-83),
and -87 (MD-87) series airplanes, and Model MD-88 airplanes;
certificated in any category; and listed in the following McDonnell
Douglas Service Bulletins:
McDonnell Douglas MD-80 Service Bulletin MD80-32-276,
dated March 31, 1995; and
McDonnell Douglas MD-80 Service Bulletin MD80-32-278,
dated March 31, 1995.
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) of this AD 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 reduce the possibility of vibration in the main landing gear
(MLG) that can adversely affect its integrity, accomplish the
following:
(a) For airplanes listed in McDonnell Douglas MD-80 Service
Bulletin MD80-32-276, dated March 31, 1995, that have not been
previously modified (installation of brake line restrictors) in
accordance with McDonnell Douglas MD-80 Service Bulletin 32-246:
Within 9 months after the effective date of this AD, install
filtered brake line restrictors in the MLG hydraulic brake system in
accordance with McDonnell Douglas MD-80 Service Bulletin MD80-32-
276, dated March 31, 1995, or Revision 1, dated October 17, 1995.
Note 2: Installation of the filtered restrictors in accordance
with the instructions contained in McDonnell Douglas MD-80 Alert
Service Bulletin MD80-A32-286, dated September 11, 1995, is
considered acceptable for compliance with paragraph (a) of this AD.
(b) For airplanes listed in McDonnell Douglas MD-80 Service
Bulletin MD80-32-278, dated March 31, 1995: Within 36 months after
the effective date of this AD, modify the hydraulic damper assembly
(by removing shims, increasing bolt torque, and incorporating
changes to increase the volume of fluid passing between the two
damper chambers) in accordance with McDonnell Douglas MD-80 Service
Bulletin MD80-32-278, dated March 31, 1995, or Revision 1, dated
September 6, 1995.
(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 3: 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.
[[Page 2409]]
(e) The installation shall be done in accordance with McDonnell
Douglas MD-80 Service Bulletin MD80-32-276, dated March 31, 1995; or
McDonnell Douglas MD-80 Service Bulletin MD80-32-276, Revision 1,
dated October 17, 1995. The modification shall be done in accordance
with McDonnell Douglas MD-80 Service Bulletin MD80-32-278, dated
March 31, 1995; or McDonnell Douglas MD-80 Service Bulletin MD80-32-
278, Revision 1, dated September 6, 1995. 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, 3855 Lakewood
Boulevard, Long Beach, California 90846, Attention: Technical
Publications Business Administration, Department C1-L51 (2-60).
Copies may be inspected 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; or at
the Office of the Federal Register, 800 North Capitol Street, NW.,
suite 700, Washington, DC.
(f) This amendment becomes effective on February 26, 1996.
Issued in Renton, Washington, on January 5, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-475 Filed 1-25-96; 8:45 am]
BILLING CODE 4910-13-P
