[Federal Register Volume 64, Number 167 (Monday, August 30, 1999)]
[Proposed Rules]
[Pages 47149-47151]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-22395]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-90-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9 and C-9 
(Military) Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain McDonnell Douglas Model 
DC-9 and C-9 (military) series airplanes. This proposal would require 
modification of the electrical power center and modification and 
overhaul of certain alternating current power relays. This proposal is 
prompted by reports indicating that the alternating current (AC) cross-
tie relay shorted out internally, which caused severe smoke and burn 
damage to the relay, aircraft wiring, and adjacent panels. The actions 
specified by the proposed AD are intended to prevent a short in the 
cross-tie relay, which may result in in-flight electrical fires.

DATES: Comments must be received by October 14, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-90-AD, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056. Comments may be inspected at this location 
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal 
holidays.
    The service information referenced in the proposed rule 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 FAA, Transport Airplane 
Directorate, 1601 Lind

[[Page 47150]]

Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane 
Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount 
Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT: Elvin Wheeler, 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) 627-5344; 
fax (562) 627-5210.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 99-NM-90-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 99-NM-90-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that the alternating 
current cross-tie relay shorted out internally on McDonnell Douglas 
Model DC-9 series airplanes, which caused severe smoke and burn damage 
to the relay, aircraft wiring, and adjacent panels. Investigation 
revealed that the electrical fire originated within the cross-tie relay 
of the power distribution system. The cause of this incident has been 
attributed to a phase-to-phase short within the relay. This condition, 
if not corrected, could result in in-flight electrical fires.

Explanation of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas DC-9 Service 
Bulletin 24-57, Revision 1, dated March 12, 1980, as amended by Change 
Notification 24-57 R1 CN2, dated June 24, 1988, which describes 
procedures for modification of the electrical power center. The 
modification of the electrical power center involves installation of 
two terminal boards, two nameplates, fourteen clamps, six current 
limiters, a mount assembly, two zees near the alternating current cross 
tie relay, and three spare alternating current cross tie relay current 
limiters and nameplate.
    The FAA also has reviewed Westinghouse Aerospace Service Bulletin 
75-703, dated June 1977, which describes procedures for modification 
and overhaul of certain alternating current power relays. The 
modification of certain alternating current power relays involves 
removal of part number 914F567-3 and installation of a -4 
configuration.
    The FAA also has reviewed McDonnell Douglas DC-9 Service Bulletin 
DC9-24-156, dated March 31, 1995, which describes procedures for 
replacement of the relays, P/N 914F567-3 or -4, with improved relays, 
P/N 9008D09.
    Accomplishment of the actions specified in the service bulletins is 
intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require accomplishment of the actions specified in 
the service bulletins described previously.

Cost Impact

    There are approximately 924 McDonnell Douglas DC-9 and C-9 
(military) series airplanes of the affected design in the worldwide 
fleet. The FAA estimates that 392 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 7 work 
hours per airplane (for Group I, 316 airplanes), and 3 work hours per 
airplane (for Group II, 76 airplanes), to accomplish the proposed 
actions, and that the average labor rate is $60 per work hour. Required 
parts would cost approximately $490 per airplane. Based on these 
figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $287,560, or $910 per airplane (for Group I airplanes), 
and $50,920, or $670 per airplane (for Group II airplanes), per 
modification.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the proposed 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 proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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:


[[Page 47151]]


    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:

McDonnell Douglas: Docket 99-NM-90-AD.

    Applicability: Model DC-9 and C-9 (military) series airplanes, 
as listed in McDonnell Douglas DC-9 Service Bulletin 24-57, Revision 
1, dated March 12, 1980; 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 a short in the cross-tie relay, which may result in 
in-flight electrical fires, accomplish the following:

Modification

    (a) Within 12 months after the effective date of this AD, modify 
the electrical power center in accordance with McDonnell Douglas DC-
9 Service Bulletin 24-57, Revision 1, dated March 12, 1980, as 
amended by Change Notification 24-57 R1 CN2, dated June 24, 1988, 
and accomplish the requirements specified in paragraph (a)(1) or 
(a)(2) of this AD.
    (1) Modify the Westinghouse alternating current power relays, 
part number (P/N) 914F567-3 (i.e., cross-tie relays, generator 
relays, auxiliary power relays, and external power relays), to a -4 
configuration, in accordance with Westinghouse Aerospace Service 
Bulletin 75-703, dated June 1977.
    (2) Replace the Westinghouse alternating current power relays, 
P/N 914F567-3 or -4 with improved relays, P/N 9008D09, in accordance 
with McDonnell Douglas DC-9 Service Bulletin DC9-24-156, dated March 
31, 1995.

Overhaul

    (b) Overhaul the Westinghouse alternating current power relays, 
in accordance with Westinghouse service bulletin 75-703, dated June 
1977, at times specified in paragraph (b)(1) or (b)(2) of this AD, 
as applicable.
    (1) For airplanes equipped with Westinghouse relay, P/N 914F567-
4, within 7,000 flight hours after accomplishing the modification 
required by paragraph (a) of this AD, overhaul the relay and repeat 
the overhaul at intervals not to exceed 7,000 flight hours.
    (2) For airplanes equipped with Westinghouse relay, P/N 9008D09, 
within 12,000 flight hours after accomplishing the modification 
required by paragraph (a) of this AD, overhaul the relay and repeat 
the overhaul at intervals not to exceed 12,000 flight hours.

Alternative Methods of Compliance

    (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.

Special Flight Permits

    (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.

    Issued in Renton, Washington, on August 23, 1999.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-22395 Filed 8-27-99; 8:45 am]
BILLING CODE 4910-13-P