[Federal Register Volume 64, Number 120 (Wednesday, June 23, 1999)]
[Rules and Regulations]
[Pages 33392-33394]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-15777]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-109-AD; Amendment 39-11201; AD 99-13-07]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model DC-9-80 Series
Airplanes, Model MD-88 Airplanes, and Model MD-90-30 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,
Model MD-88 airplanes, and Model MD-90-30 airplanes; that requires
repetitive inspections to detect cracking of the main landing gear
(MLG) shock strut pistons, and replacement of a cracked piston with a
new or serviceable part. This amendment is prompted by reports
indicating that, while an airplane was positioned on the taxiway, the
right MLG shock strut piston failed due to fatigue cracking. The
actions specified by this AD are intended to detect and correct such
fatigue cracking, which could result in failure of the piston, and
consequent damage to the airplane structure or injury to the passengers
and flightcrew.
DATES: Effective July 28, 1999.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of July 28, 1999.
ADDRESSES: The service information referenced in this AD may be
obtained from Boeing Commercial Aircraft Group, Long Beach Division,
3855 Lakewood Boulevard, Long Beach, California 90846, Attention:
Technical Publications Business Administration, Dept. 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, Transport Airplane Directorate,
Los Angeles Aircraft Certification Office, 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: Brent Bandley, Aerospace Engineer,
Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los
Angeles Aircraft Certification Office, 3960 Paramount Boulevard,
Lakewood, California 90712-4137; telephone (562) 627-5237; fax (562)
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, Model MD-88 airplanes, and Model MD-90-30
airplanes was published in the Federal Register on September 8, 1998
(63 FR 47443). That action proposed to require repetitive inspections
to detect cracking of the main landing gear (MLG) shock strut pistons,
and replacement of a cracked piston with a new or serviceable part.
Comments
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Support for the Proposal
Three commenters support the proposal, and three commenters have no
objection to the proposal.
Request To Revise Applicability
One commenter requests that the proposed rule be revised to provide
for airplanes on which an existing piston is replaced with a modified
piston having certain part numbers. The commenter provides no
justification for its request.
The FAA concurs with the commenter's request to include a provision
for operators who replace an existing piston with a modified piston.
The FAA has determined that Boeing will produce modified pistons having
the part numbers referenced by the commenter. The FAA finds that an
airplane on which a modified piston, having part number 5935347-517 or
5935347-519, is installed is not subject to the requirements of this
AD. Therefore, the applicability statement of this final rule has been
revised to include only airplanes that are equipped with a MLG shock
strut piston having part number 5935347-1 through 509 inclusive,
5935347-511, or 5935347-513.
Request To Revise Cost Impact Information
Two commenters request that the cost impact information in the
proposed rule be revised to more accurately represent the number of
work hours necessary to accomplish the inspection. One commenter
estimates that it will take 14 work hours to accomplish the initial
inspection and 12 work hours to
[[Page 33393]]
accomplish each repetitive inspection. The other commenter states that
the work hours should reflect the estimates provided in the service
bulletin.
The FAA does not concur with the commenters' request to revise the
cost impact information. The cost impact information, which is restated
below, describes only the ``direct'' costs of the specific actions
required by this AD. The estimated number of work hours represents the
time necessary to perform only the actions actually required by this
AD. The FAA recognizes that, in accomplishing the requirements of any
AD, operators may incur ``incidental'' costs in addition to the
``direct'' costs. However, the cost analysis in AD rulemaking actions
typically does not include incidental costs, such as the time required
to gain access and close up, planning time, or time necessitated by
other administrative actions. Because incidental costs may vary
significantly from operator to operator, they are almost impossible to
calculate. No change to the final rule is necessary in this regard.
Request To Reference Specific Chapters of Component Maintenance Manual
One commenter requests that paragraph (a)(2) of the proposed AD be
revised to reference McDonnell Douglas Component Maintenance Manual
(CMM) Chapter 32-17-01 or 32-17-02, instead of All Operator Letter
(AOL) 9-2153, dated June 27, 1991, as the appropriate source of service
information for initial inspection of the MLG shock strut piston
accomplished prior to the effective date of this AD on McDonnell
Douglas Model DC-9-80 series airplanes and Model MD-88 airplanes. The
commenter also requests that the proposed rule be revised to provide
credit for airplanes on which major overhaul is accomplished in
accordance with CMM Chapter 32-17-01 or 32-17-02, so that such
airplanes are subject to a repetitive inspection interval of 2,500
flight cycles after overhaul. The commenter justifies its requests by
stating that AOL 9-2153 does not describe inspection procedures, but
specifies only that inspection methods will be added to the CMM.
The FAA does not concur with the commenter's request to reference
specific chapters of the CMM instead of AOL 9-2153. The FAA cannot
reference appropriate revision levels of CMM sections by citing
specific dates, as it can with service bulletins and AOL's. Therefore,
as stated in the proposal, the FAA intends the compliance time stated
in paragraph (a)(2) to apply only to Model DC-9-80 series airplanes and
Model MD-88 airplanes that are inspected or overhauled prior to the
effective date of this AD in accordance with the instructions
incorporated into the CMM per AOL 9-2153. With regard to the
commenter's request for credit for airplanes overhauled in accordance
with the applicable chapters of the CMM, the FAA finds that paragraph
(a)(2) clearly states that inspection is required within 2,500 landings
after major overhaul in accordance with AOL 9-2153. No change to the
final rule is necessary in this regard.
Explanation of Change to Final Rule
Paragraph (b) of the final rule has been revised to provide
clarification. The FAA finds that the last sentence of paragraph (b) in
the proposal did not make it clear that replacement of a cracked MLG
shock strut piston with a new or serviceable piston allows the
compliance threshold for the inspection to be ``reset'' to 10,000 total
landings on the piston. Therefore, the last sentence of paragraph (b)
of the final rule has been revised to read, ``Thereafter, repeat the
inspections required by paragraph (a) of this AD prior to the
accumulation of 10,000 total landings on the MLG shock strut piston.''
Conclusion
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 described
previously. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
Cost Impact
There are approximately 1,250 airplanes of the affected design in
the worldwide fleet. The FAA estimates that 828 airplanes of U.S.
registry will be affected by this AD, that it will take approximately 4
work hours per airplane to accomplish the required inspection, and that
the average labor rate is $60 per work hour. Based on these figures,
the cost impact of the inspection required by this AD on U.S. operators
is estimated to be $198,720, or $240 per airplane, per inspection
cycle.
Should an operator be required to accomplish the replacement of an
MLG shock strut piston, it will take approximately 16 work hours per
airplane to accomplish, at an average labor rate of $60 per work hour.
Required parts will cost approximately $107,070 per airplane. Based on
these figures, the cost impact of the replacement required by this AD
on U.S. operators is estimated to be $108,030 per airplane.
The cost impact figures discussed above are 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.
Regulatory Impact
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 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
99-13-07 McDonnell Douglas: Amendment 39-11201. Docket 98-NM-109-
AD.
Applicability: Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83
(MD-83), and
[[Page 33394]]
DC-9-87 (MD-87) series airplanes, Model MD-88 airplanes, and Model
MD-90-30 airplanes; equipped with a main landing gear (MLG) shock
strut piston having part number 5935347-1 through -3509 inclusive,
5935347-511, or 5935347-513; 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 request approval for an
alternative method of compliance in accordance with paragraph (e) of
this AD. The request should include an assessment of the effect of
the modification, alteration, or repair on the unsafe condition
addressed by this AD; and, if the unsafe condition has not been
eliminated, the request should include specific proposed actions to
address it.
Compliance: Required as indicated, unless accomplished
previously.
To detect and correct fatigue cracking of the MLG shock strut
pistons, which could result in failure of the piston, and consequent
damage to the airplane structure or injury to the passengers and
flightcrew, accomplish the following:
Initial Inspection
(a) Perform fluorescent dye penetrant and fluorescent magnetic
particle inspections to detect cracking of an MLG shock strut
piston, in accordance with McDonnell Douglas Alert Service Bulletin
MD80-32A308, dated March 5, 1998, or MD80-32A308, Revision 01, dated
May 12, 1998 [for Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83
(MD-83), and DC-9-87 (MD-87) series airplanes, and Model MD-88
airplanes]; or MD90-32A030, dated March 26, 1998, or MD90-32A030,
Revision 01, dated May 11, 1998 (for Model MD-90-30 airplanes); as
applicable. Perform the inspections at the later of the times
specified in paragraphs (a)(1) and (a)(2) of this AD.
(1) Prior to the accumulation of 10,000 total landings on an MLG
shock strut piston, or within 6 months after the effective date of
this AD, whichever occurs later.
(2) Within 2,500 landings after a major overhaul and initial
inspection of the MLG shock strut piston accomplished prior to the
effective date of this AD, in accordance with McDonnell Douglas All
Operator Letter 9-2153 [for Model DC-9-81 (MD-81), DC-9-82 (MD-82),
DC-9-83 (MD-83), and DC-9-87 (MD-87) series airplanes, and Model MD-
88 airplanes], or McDonnell Douglas Component Maintenance Manual,
Chapter 32-17-01 (for Model MD-90-30 airplanes).
Corrective Actions
(b) Condition 1. If any cracking is detected, prior to further
flight, replace any cracked MLG shock strut piston with a new or
serviceable piston, in accordance with McDonnell Douglas Alert
Service Bulletin MD80-32A308, dated March 5, 1998, or MD80-32A308,
Revision 01, dated May 12, 1998 [for Model DC-9-81 (MD-81), DC-9-82
(MD-82), DC-9-83 (MD-83), and DC-9-87 (MD-87) series airplanes, and
Model MD-88 airplanes]; or MD90-32A030, dated March 26, 1998, or
MD90-32A030, Revision 01, dated May 11, 1998 (for Model MD-90-30
airplanes); as applicable. Thereafter, repeat the inspections
required by paragraph (a) of this AD prior to the accumulation of
10,000 total landings on the MLG shock strut piston.
(c) Condition 2. If no cracking is detected, repeat the
fluorescent dye penetrant and fluorescent magnetic particle
inspections thereafter at intervals not to exceed 2,500 landings, in
accordance with McDonnell Douglas Alert Service Bulletin MD80-
32A308, dated March 5, 1998, or MD80-32A308, Revision 01, dated May
12, 1998 [for Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-
83), and DC-9-87 (MD-87) series airplanes, and Model MD-88
airplanes]; or MD90-32A030, dated March 26, 1998, or MD90-32A030,
Revision 01, dated May 11, 1998 (for Model MD-90-30 airplanes); as
applicable.
Spares
(d) As of the effective date of this AD, no person shall install
on any airplane a replacement MLG shock strut piston, part number
5935347-509, -511, or -513, or an MLG assembly from an operator's
spares inventory, unless those components have been inspected in
accordance with the requirements specified by paragraph (a) of this
AD.
Alternative Methods of Compliance
(e) 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.
Special Flight Permits
(f) 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.
Incorporation by Reference
(g) The actions shall be done in accordance with McDonnell
Douglas Alert Service Bulletin MD80-32A308, dated March 5, 1998;
McDonnell Douglas Alert Service Bulletin MD80-32A308, Revision 01,
dated May 12, 1998; McDonnell Douglas Alert Service Bulletin MD90-
32A030, dated March 26, 1998; or McDonnell Douglas Alert Service
Bulletin MD90-32A030, Revision 01, dated May 11, 1998. 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 Boeing Commercial Aircraft Group,
Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California
90846, Attention: Technical Publications Business Administration,
Dept. C1-L51 (2-60). 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, 3960 Paramount Boulevard, Lakewood,
California; or at the Office of the Federal Register, 800 North
Capitol Street, NW., suite 700, Washington, DC.
(h) This amendment becomes effective on July 28, 1999.
Issued in Renton, Washington, on June 15, 1999.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-15777 Filed 6-22-99; 8:45 am]
BILLING CODE 4910-13-U
