[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