[Federal Register Volume 61, Number 180 (Monday, September 16, 1996)]
[Rules and Regulations]
[Pages 48617-48618]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-23243]



[[Page 48617]]

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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-221-AD; Amendment 39-9756; AD 96-19-09]
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 adopts a new airworthiness directive (AD), 
applicable to certain McDonnell Douglas Model DC-9-80 series airplanes 
and Model MD-88 airplanes, that requires a one-time inspection to 
detect cracking of the main landing gear (MLG) pistons, and repair or 
replacement of the pistons with new or serviceable parts, if necessary. 
This amendment is prompted by reports of failure of the MLG pistons 
that occurred during towing of the airplanes. The actions specified by 
this AD are intended to prevent fatigue cracking of the MLG pistons, 
which could result in failure of the pistons and subsequent damage to 
the airplane structure or injury to airplane occupants.

DATES: Effective October 21, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of October 21, 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: Brent Bandley, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone 
(310) 627-5237; 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 April 15, 1996 (61 FR 16413). That action proposed 
to require a one-time dye penetrant and magnetic particle inspection to 
detect cracking of the main landing gear (MLG) pistons, and repair or 
replacement of the pistons with new or serviceable parts, if necessary.
    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

    One commenter supports the proposed rule.

Request to Review Availability of Spare Parts

    Several commenters request that, prior to the issuance of a final 
rule, the FAA consider the availability of spare MLG pistons. The 
commenters are concerned that ample replacement parts may not be 
available to the fleet in a timely manner.
    The FAA has contacted the McDonnell Douglas Corporation, who 
advises that it has anticipated the need for additional spares and is 
addressing that issue with the gear manufacturer. Additionally, the FAA 
has approved procedures for removal of cracks from MLG pistons. Cracked 
pistons have been found on several aircraft so far, and the approved 
repairs (rather than replacement) have been applicable to most of those 
pistons.

Request to Extend Compliance Time for Inspection

    Two commenters request that the proposed compliance time be 
extended. One commenter indicates that the proposed compliance time of 
12 months or 1,500 landings (whichever occurs first) is not acceptable 
due to a lack of spare parts. The commenter suggests that a compliance 
time of 18 months or 3,000 landings (whichever occurs first) will 
provide an acceptable level of safety.
    The FAA does not concur with the commenters' request. In developing 
an appropriate compliance time for this AD, the FAA considered not only 
the safety implications, but parts availability and normal maintenance 
schedules for timely accomplishment of the inspection of the affected 
fleet. In consideration of these factors, the FAA determined that the 
compliance time, as proposed, represents an appropriate interval in 
which the inspection can be accomplished in a timely manner within the 
fleet and an adequate level of safety can still be maintained. 
Additionally, as discussed above, parts availability should not pose a 
problem for affected operators. However, the provisions of paragraph 
(f) of this AD afford operators the opportunity to request an 
adjustment of the compliance time, provided that adequate justification 
is presented to support such a request.

Request to Revise Applicability of the Rule

    One commenter requests that the FAA revise the applicability of the 
proposed AD to exempt from the AD requirements all Model MD-88 
airplanes that have an improved or reworked/reidentified MLG piston.
    The FAA concurs with the commenter's request. The FAA finds that 
the only Model MD-88 airplanes that are subject to the addressed unsafe 
condition are those airplanes equipped with MLG pistons having part 
numbers 5935347-1 through 5935347-509, inclusive. The FAA has revised 
the applicability of the final rule accordingly.

Request to Cite Additional Service Information

    One commenter requests that the FAA revise the proposal to cite the 
original issue of McDonnell Douglas Service Bulletin MD80-32-277 as an 
additional source of service information for accomplishment of the 
proposed inspection.
    The FAA concurs. The FAA has determined that the original issue of 
the service bulletin contains the same inspection criteria outlined in 
Revision 1 of the service bulletin, which was referenced in the 
proposal as the appropriate source for service information. The FAA 
considers accomplishment of the inspection in accordance with the 
original issue of the service bulletin to be acceptable for compliance 
with this AD. Paragraph (a) of the final rule has been revised 
accordingly.

Request to Revise Work Hour Estimate

    One commenter considers that the cost estimate presented in the 
preamble to the proposal was too low. The commenter indicates that the 
cost estimate should be revised to specify that the proposed inspection 
necessitates 8 work hours to accomplish.
    The FAA does not concur that the number of work hours required is 
higher than approximated previously. The airplane manufacturer advises 
that it

[[Page 48618]]

has worked extensively with operators of the affected airplanes to 
determine the length of time necessary for accomplishment of the 
required inspection. Several airplanes have already been inspected, and 
2 work hours, as specified in the proposal, has been shown to be a 
reasonable estimate for accomplishment of the inspection.

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 1,119 Model DC-9-80 series airplanes and 
Model MD-88 airplanes of the affected design in the worldwide fleet. 
The FAA estimates that 609 airplanes of U.S. registry will be affected 
by this AD, that it will take approximately 2 work hours per airplane 
to accomplish the required actions, and that the average labor rate is 
$60 per work hour. Based on these figures, the cost impact of the AD on 
U.S. operators is estimated to be $73,080, or $120 per airplane.
    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 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:

 96-19-09 McDonnell Douglas:  Amendment 39-9756. Docket 95-NM-221-
AD.

     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 equipped with main landing gear (MLG) pistons having part 
numbers 5935347-1 through 5935347-509 inclusive; as listed in 
McDonnell Douglas Service Bulletin MD80-32-277, Revision 01, dated 
February 23, 1996; 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 prevent fatigue cracking of the main landing gear (MLG) 
pistons, which could result in failure of the pistons and subsequent 
damage to the airplane structure or injury to airplane occupants, 
accomplish the following:
    (a) Perform a one-time dye penetrant and magnetic particle 
inspection to detect cracking of the MLG pistons, in accordance with 
McDonnell Douglas Service Bulletin MD80-32-277, dated October 4, 
1995, or Revision 01, dated February 23, 1996, at the later of the 
times specified in paragraphs (a)(1) and (a)(2) of this AD.
    (1) Prior to the accumulation of 4,000 total landings on the MLG 
piston.
    (2) Within 1,500 landings or 12 months after the effective date 
of this AD, whichever occurs first.
    (b) If no cracking is found, no further action is required by 
this AD.
    (c) If any cracking is found that is within the limits specified 
in McDonnell Douglas Service Bulletin MD80-32-277, Revision 01, 
dated February 23, 1996, prior to further flight, repair in 
accordance with the service bulletin.
    (d) If any cracking is found that is outside the limits 
specified in McDonnell Douglas Service Bulletin MD80-32-277, 
Revision 01, dated February 23, 1996, prior to further flight, 
replace the MLG piston with a new or serviceable part in accordance 
with the service bulletin.
    (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.

    (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.
    (g) The actions shall be done in accordance with McDonnell 
Douglas Service Bulletin MD80-32-277, dated October 4, 1995; or 
McDonnell Douglas Service Bulletin MD80-32-277, Revision 01, dated 
February 23, 1996. 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.
    (h) This amendment becomes effective on October 21, 1996.

    Issued in Renton, Washington, on September 5, 1996.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-23243 Filed 9-13-96; 8:45 am]
BILLING CODE 4910-13-U