[Federal Register Volume 64, Number 27 (Wednesday, February 10, 1999)]
[Rules and Regulations]
[Pages 6521-6522]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-3035]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-269-AD; Amendment 39-11030; AD 99-04-06]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model MD-90-30 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain McDonnell Douglas Model MD-90-30 series 
airplanes, that requires modification of the right and left main 
landing gear (MLG) hydraulic damper assemblies or replacement of the 
MLG hydraulic damper assemblies with modified and reidentified 
hydraulic damper assemblies. This amendment is prompted by reports 
indicating that, during overhauls, the MLG hydraulic dampers assemblies 
failed or had damaged spring retainers due to insufficient material 
thickness of the spring retainers. The actions specified by this AD are 
intended to prevent failure of the hydraulic damper assemblies of the 
MLG, which could result in vibration damage and collapse of the MLG.

DATES: Effective March 17, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 17, 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: Albert Lam, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130L, FAA, Transport Airplane 
Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount 
Boulevard, Lakewood, California 90712-4137; telephone (562) 627-5346; 
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 
MD-90-30 series airplanes was published in the Federal Register on 
October 21, 1998 (63 FR 56125). That action proposed to require 
modification of the right and left main landing gear (MLG) hydraulic 
damper assemblies or replacement of the MLG hydraulic damper assemblies 
with modified and reidentified hydraulic damper assemblies.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the two comments received.
    One commenter supports the proposed rule.

Comment Concerning Availability of Parts

    One commenter states no objection to the proposed rule, however, 
the commenter questions whether parts will be available within the 
proposed compliance time. The FAA has consulted with the manufacturer, 
and finds that parts will be available within the required compliance 
time.

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 as proposed.

Cost Impact

    There are approximately 111 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 40 airplanes of U.S. registry 
will be affected by this AD.
    It will take approximately 18 work hours per airplane (including 
access, removal, and closeup) to accomplish the required modification, 
at an average labor rate of $60 per work hour. Required parts will cost 
approximately $598 per airplane. Based on these figures, the cost 
impact of the AD on U.S. operators is estimated to be $1,678 per 
airplane.
    It will take approximately 5 work hours per airplane to accomplish 
the required replacement at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the replacement required by 
this AD on U.S. operators is estimated to be $300 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no

[[Page 6522]]

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:

99-04-06  McDonnell Douglas: Amendment 39-11030. Docket 98-NM-269-
AD.

    Applicability: Model MD-90-30 series airplanes, as listed in 
McDonnell Douglas Service Bulletin MD90-32-032, dated July 8, 1998; 
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 (c) 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 failure of the hydraulic damper assemblies of the 
main landing gear (MLG), which could result in vibration damage and 
collapse of the MLG, accomplish the following:
    (a) Within 2 years after the effective date of this AD, 
accomplish the requirements specified in either paragraph (a)(1) or 
(a)(2) of this AD.
    (1) Modify the right and left MLG hydraulic damper assemblies in 
accordance with McDonnell Douglas Service Bulletin MD90-32-032, 
dated July 8, 1998; or
    (2) Replace the right and left MLG hydraulic damper assemblies 
with modified and reidentified hydraulic damper assemblies having 
part number (P/N) SR09320057-7005, SR09320057-7007, SR09320057-7009, 
or 5923142-5513, in accordance with paragraph B.5. of the 
Accomplishment Instructions of the service bulletin.
    (b) As of the effective date of this AD, no person shall install 
on any airplane a damper sub assembly having P/N SR09320057-9, 
SR09320057-17, or 5923142-5017; or a damper assembly having P/N 
SR09320057-7001, SR09320057-7003, or 5923142-5511, unless the part 
is modified in accordance with paragraph (a)(1) of this AD.
    (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 2: 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.
    (e) The modification and replacement shall be done in accordance 
with McDonnell Douglas Service Bulletin MD90-32-032, dated July 8, 
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.
    (f) This amendment becomes effective on March 17, 1999.

    Issued in Renton, Washington, on February 2, 1999.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-3035 Filed 2-9-99; 8:45 am]
BILLING CODE 4910-13-U