[Federal Register Volume 64, Number 52 (Thursday, March 18, 1999)]
[Rules and Regulations]
[Pages 13330-13333]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-6216]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-292-AD; Amendment 39-11077; AD 99-06-13]
RIN 2120-AA64


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 supersedes an existing airworthiness directive 
(AD), applicable to certain McDonnell Douglas Model DC-9-80 series 
airplanes and Model MD-88 airplanes, that currently requires 
inspection(s) to detect fatigue cracking of the shock strut cylinder of 
the main landing gear (MLG), and replacement of any cracked shock strut 
cylinder with a serviceable part. That AD also provides for 
installation of brake line hydraulic restrictors on the MLG brake 
systems, which, if accomplished, terminates the repetitive inspections. 
This amendment requires that the subject inspection be accomplished 
repetitively following installation of brake line hydraulic 
restrictors. This amendment is prompted by an additional report of 
fatigue cracking and subsequent fracturing of the shock strut cylinder 
of the MLG. The actions specified by this AD are intended to prevent 
collapse of the MLG due to fracturing of the shock strut cylinder.


[[Page 13331]]


DATES: Effective April 22, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of April 22, 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, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712; 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) by superseding AD 95-22-06, 
amendment 39-9413 (60 FR 54417, October 24, 1995), which is applicable 
to certain McDonnell Douglas Model DC-9-80 series airplanes and Model 
MD-88 airplanes, was published in the Federal Register on July 30, 1998 
(63 FR 40666). The action proposed to continue to require inspection(s) 
to detect fatigue cracking of the shock strut cylinder of the main 
landing gear (MLG), and replacement of any cracked shock strut cylinder 
with a serviceable part. That action also proposed to continue to 
provide for installation of brake line hydraulic restrictors on the MLG 
brake systems, which, if accomplished, terminates the repetitive 
inspections. That action proposed to require that the subject 
inspection be accomplished repetitively following installation of brake 
line hydraulic restrictors.

Comments Received

    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 Proposed Rule

    Several commenters support the proposed rule.

Request To Revise Wording

    One commenter requests that the phrase ``for airplanes'' in 
paragraphs (a)(1), (a)(2), and (a)(3) of the proposed AD be revised to 
``for MLG shock strut cylinders.'' The commenter points out that MLG's 
are replaceable units that can be ``time continued'' on a different 
airplane. The FAA concurs. The FAA's intent was that compliance time of 
those paragraphs be specified in the landings accumulated on MLG's 
since accomplishment of the brake line hydraulic restrictor 
installation, rather than the landings that an airplane had 
accumulated. Therefore, the FAA has revised paragraphs (a)(1), (a)(2), 
and (a)(3) of the final rule to clarify this point.

Requests To Revise Repetitive Inspection Intervals

    One commenter requests that the repetitive inspection interval of 
the proposed AD be extended from 1,200 landings to 2,000 landings. The 
commenter states that such an extension would allow most inspections to 
occur within its check hangar environment.
    The FAA does not concur with the commenter's request. The commenter 
provided no technical justification for revising this interval as 
requested. Fatigue cracking and subsequent fracturing of the shock 
strut cylinder of the MLG is a significant safety issue, and the FAA 
has determined that the inspection interval, as proposed, is warranted, 
based on the effectiveness of the inspection procedure to detect 
cracks, and the rate of crack growth in the shock strut cylinder of the 
MLG. The FAA considered not only those safety issues in developing an 
appropriate compliance time for this action, but the recommendations of 
the manufacturer, the availability of any necessary repair parts, and 
the practical aspect of accomplishing the required inspection within an 
interval of time that parallels normal scheduled maintenance for the 
majority of affected operators. However, under the provisions of 
paragraph (d)(1) 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 revise the proposed AD to 
simplify and clarify that inspections should be performed at a minimum 
of 4,800 cycles past restrictor installation. The commenter suggests 
that the proposed AD be revised to read, ``Perform repetitive 
inspections at intervals not to exceed 1,200 landings until a minimum 
of 4,800 landings has accumulated since brake line restrictor 
installation. A minimum of two (2) repetitive inspections, with at 
least 1,000 cycles accrued between inspections, shall be performed 
regardless of the total number of cycles accumulated since restrictor 
installation.'' The commenter states that such a statement will ensure 
that inspections are performed past 4,800 cycles from restrictor 
installation and will allow credit for inspections performed prior to 
issuance of McDonnell Douglas Alert Service Bulletin MD80-32A286, 
Revision 02, dated October 2, 1997.
    The FAA does not concur with the commenter's request. The FAA 
points out that the subject repetitive inspection intervals are 
essentially identical to those specified in McDonnell Douglas Alert 
Service Bulletin MD80-32A286, Revision 03, dated May 28, 1998 (which is 
referenced in the proposed AD as the appropriate source of service 
information for accomplishment of the required actions). The FAA finds 
that using wording that is significantly different from that of the 
alert service bulletin may cause more confusion to operators. 
Therefore, the FAA finds that no change to the final rule is necessary.

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 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.

Cost Impact

    There are approximately 1,011 McDonnell Douglas Model DC-9-80 
series airplanes and Model MD-88 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 625 airplanes of U.S. 
registry will be affected by this AD.
    The dye penetrant and magnetic particle inspections that are 
required in this AD action will take approximately 4 work hours per 
airplane to accomplish, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the dye penetrant and 
magnetic particle inspections required by this AD on U.S. operators is 
estimated to be $150,000, or $240 per airplane, per inspection cycle.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the requirements of this AD 
action, and that no operator would accomplish

[[Page 13332]]

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 removing amendment 39-9413 (60 FR 
54417, October 24, 1995), and by adding a new airworthiness directive 
(AD), amendment 39-11077, to read as follows:

99-06-13  McDonnell Douglas: Amendment 39-11077. Docket 97-NM-292-
AD. Supersedes AD 95-22-06, Amendment 39-9413.

    Applicability: 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; as listed in McDonnell Douglas Alert Service Bulletin 
MD80-32A286, dated September 11, 1995; 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 (d)(1) 
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 prevent collapse of the main landing gear (MLG) due to 
fracturing of the shock strut cylinder, accomplish the following:

    Note 2: Where there are differences between the referenced alert 
service bulletin and the AD, the AD prevails.

Inspections

    (a) Perform dye penetrant and magnetic particle inspections to 
detect cracking of the shock strut cylinder of the MLG, in 
accordance with McDonnell Douglas Alert Service Bulletin MD80-
32A286, Revision 03, dated May 28, 1998; at the time specified in 
paragraph (a)(1), (a)(2), or (a)(3) of this AD, as applicable.

    Note 3: Inspections accomplished prior to the effective date of 
this AD in accordance with McDonnell Douglas Alert Service Bulletin 
MD80-32A286, Revision 02, dated October 2, 1997, are considered 
acceptable for compliance with paragraph (a) of this AD.

    (1) For MLG shock strut cylinders that, as of the effective date 
of this AD, have accumulated less than 1,200 landings since 
accomplishment of the brake line hydraulic restrictor installation: 
Inspect within 1,200 landings after the effective date of this AD. 
Repeat the inspections thereafter at intervals not to exceed 1,200 
landings for a total of 4 inspections.
    (2) For MLG shock strut cylinders that, as of the effective date 
of this AD, have accumulated greater than or equal to 1,200 landings 
and less than 2,400 landings since accomplishment of the brake line 
hydraulic restrictor installation: Inspect within 1,200 landings 
after the effective date of this AD. Repeat the inspections 
thereafter at intervals not to exceed 1,200 landings for a total of 
3 inspections.
    (3) For MLG shock strut cylinders that, as of the effective date 
of this AD, have accumulated greater than or equal to 2,400 landings 
since accomplishment of the brake line hydraulic restrictor 
installation: Inspect within 1,200 landings after the effective date 
of this AD. Repeat the inspections thereafter at intervals not to 
exceed 1,200 landings for a total of 2 inspections.

Corrective Actions

    (b) If any cracking is detected during any inspection required 
by paragraph (a) of this AD, prior to further flight, accomplish 
either paragraph (b)(1) or (b)(2) of this AD in accordance with 
McDonnell Douglas Alert Service Bulletin MD80-32A286, Revision 03, 
dated May 28, 1998.
    (1) Replace the shock strut cylinder with a crack-free 
serviceable part and, thereafter, repeat the inspections required by 
paragraph (a) of this AD, at the time specified in paragraph (a)(1), 
(a)(2), or (a)(3) of this AD, as applicable. Or
    (2) Replace the shock strut cylinder with a new shock strut 
cylinder. Accomplishment of the replacement constitutes terminating 
action for the repetitive inspection requirements of paragraph (a) 
of this AD.

    Note 4: Replacements accomplished prior to the effective date of 
this AD in accordance with McDonnell Douglas Alert Service Bulletin 
MD80-32A286, Revision 02, dated October 2, 1997, are considered 
acceptable for compliance with paragraph (b) of this AD.

Spares

    (c) As of the effective date of this AD, no person shall install 
on any airplane an MLG shock strut cylinder or MLG assembly unless 
that part has been inspected and found to be crack free, in 
accordance with McDonnell Douglas Alert Service MD80-32A286, 
Revision 02, dated October 2, 1997, or Revision 03, dated May 28, 
1998.

Alternative Methods of Compliance

    (d)(1) 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 5: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (d)(2) Alternative methods of compliance, approved previously in 
accordance with AD 95-22-06, amendment 39-9413, are approved as 
alternative methods of compliance with this AD.

Special Flight Permits

    (e) 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

    (f) The actions shall be done in accordance with McDonnell 
Douglas Alert Service Bulletin MD80-32A286, Revision 03, dated May 
28, 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

[[Page 13333]]

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.
    (g) This amendment becomes effective on April 22, 1999.

    Issued in Renton, Washington, on March 9, 1999.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-6216 Filed 3-17-99; 8:45 am]
BILLING CODE 4910-13-U