[Federal Register Volume 59, Number 208 (Friday, October 28, 1994)]
[Unknown Section]
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From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-26366]


  Federal Register / Vol. 59, No. 208 / Friday, October 28, 1994 /   
[Federal Register: October 28, 1994]


                                                   VOL. 59, NO. 208

                                           Friday, October 28, 1994
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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-78-AD; Amendment 39-9052; AD 94-22-03]


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 modification of the power 
transfer unit (PTU). This amendment is prompted by reports of fatigue 
cracks found in the drain port housings of the PTU's on several 
airplanes. The actions specified by this AD are intended to prevent 
failure of the PTU housing due to fatigue cracking, which could result 
in the loss of both hydraulic systems (until the PTU is shut off).

DATES: Effective October 28, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 28, 1994.

ADDRESSES: The service information referenced in this AD may be 
obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach, 
California 90801-1771, Attention: Business Unit Manager, Technical 
Administrative Support, Dept. L51, M.C. 2-98. 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, 3229 East Spring Street, Long Beach, 
California; or at the Office of the Federal Register, 800 North Capitol 
Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Walter Eierman, Systems and Equipment 
Branch, ANM-131L, FAA, Transport Airplane Directorate, Los Angeles ACO, 
3229 East Spring Street, Long Beach, California 90806-2425; telephone 
(310) 988-5336; fax (310) 988-5210.

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 July 27, 1994 (59 FR 38146). That action proposed 
to require modification of the power transfer unit (PTU).
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter supports the proposal.
    Two commenters requested that the proposed compliance time of 
``14,300 flight cycles on the PTU or 9 months after the effective date 
of the AD, whichever occurs later,'' be extended. These commenters are 
concerned that they will be unable to modify their affected fleets 
within the proposed compliance time due to a possible problem in the 
availability of an ample number of required parts from the 
manufacturer. The FAA does not concur with the commenter's request to 
extend the compliance time. In developing an appropriate compliance 
time for this action, the FAA considered not only the degree of urgency 
associated with addressing the subject unsafe condition, but the 
availability of required parts and the practical aspect of installing 
the required modification within a maximum interval of time allowable 
for all affected airplanes to continue to operate without compromising 
safety. The FAA has been advised that an ample number of required parts 
will be available for modification of the U.S. fleet within the 
proposed compliance period. However, under the provisions of paragraph 
(b) of the final rule, the FAA will consider requests for adjustments 
to the compliance time if data are submitted to substantiate that such 
an adjustment would provide an acceptable level of safety.
    The applicability of the final rule has been revised to delete the 
reference to Model ``DC-9-84 (MD-84).'' This inclusion of this 
reference was in error; no such model of airplane exists.
    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 change previously 
described. The FAA has determined that this change will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    There are approximately 1,074 Model DC-9-80 series airplanes and 
Model MD-88 airplanes of the affected design in the worldwide fleet. 
The FAA estimates that 578 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. Required parts will cost approximately $2,912 per 
airplane. Based on these figures, the total cost impact of the AD on 
U.S. operators is estimated to be $1,752,496, or $3,032 per airplane.
    The total 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.
    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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

94-22-03  McDonnell Douglas: Amendment 39-9052. Docket 94-NM-78-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; as listed in McDonnell Douglas Service Bulletin 29-53, 
Revision 1, dated April 21, 1994; excluding airplanes equipped with 
Vickers PV3-160 Engine Driven Pumps; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent loss of both hydraulic systems due to the failure of 
the housings of the power transfer unit (PTU), accomplish the 
following:
    (a) Prior to or upon accumulation of 14,300 flight cycles on the 
PTU, or within 9 months after the effective date of this AD, 
whichever occurs later, modify the PTU assembly, part number 
4100310, in accordance with McDonnell Douglas Service Bulletin 29-
53, Revision 1, dated April 21, 1994.
    (b) 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: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Los Angeles ACO.

    (c) 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.
    (d) The modification shall be done in accordance with McDonnell 
Douglas Service Bulletin 29-53, Revision 1, dated April 21, 1994. 
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, P.O. 
Box 1771, Long Beach, California 90801-1771, Attention: Business 
Unit Manager, Technical Administrative Support, Dept. L51, M.C. 2-
98. 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, 3229 East Spring Street, Long Beach, California; or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.
    (e) This amendment becomes effective on November 28, 1994.

    Issued in Renton, Washington, on October 19, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-26366 Filed 10-27-94; 8:45 am]
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