[Federal Register Volume 66, Number 141 (Monday, July 23, 2001)]
[Proposed Rules]
[Pages 38170-38173]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-17585]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-291-AD]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Model DC-9-10, -20, -
30, -40, and -50 Series Airplanes; C-9 (Military) Airplanes; Model DC-
9-81, -82, -83, and -87 Series Airplanes; and Model MD-88 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-9-10, -20, -30, -40, and -50 series airplanes; C-9 (military) 
airplanes; Model DC-9-81, -82, -83, and -87 series airplanes; and Model 
MD-88 airplanes. This proposal would require an inspection of the power 
feeder bus cables of the auxiliary power unit (APU) for overheat damage 
between certain fuselage stations; and corrective action(s), if 
necessary. This action is necessary to prevent loose terminal stud 
connections and consequent damage to the small copper terminals, which 
could result in overheating of the wires at the terminal strip. Such 
overheating could result in electrical failure, which could result in 
smoke and fire in the electrical/electronic compartment. This action is 
intended to address the identified unsafe condition.

DATES: Comments must be received by September 6, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-291-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 99-NM-291-AD'' in the subject line and need not be 
submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    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: Data 
and Service Management, Dept. C1-L5A (D800-0024). This information may 
be examined at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the FAA, 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, 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 action may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.

[[Page 38171]]

     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 99-NM-291-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-291-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Background

    In July 1996, a Boeing Model 747 series airplane was involved in an 
accident. As part of re-examining all aspects of the service experience 
of the airplane involved in the accident, the FAA participated in 
design review and testing to determine possible sources of ignition in 
center fuel tanks. As part of the review, we examined fuel system 
wiring with regard to the possible effects that wire degradation may 
have on arc propagation.
    In 1997 in a parallel preceding, at the recommendation of the White 
House Commission on Aviation Safety and Security, the FAA expanded its 
Aging Transport Program to include non-structural systems and assembled 
a team for evaluating these systems. This team performed visual 
inspections of certain transport category airplanes for which 20 years 
or more had passed since date of manufacture. In addition, the team 
gathered information from interviews with FAA Principal Maintenance 
Inspectors and meetings with representatives of airplane manufacturers. 
This evaluation revealed that the length of time in service is not the 
only cause of wire degradation; inadequate maintenance, contamination, 
improper repair, and mechanical damage are all contributing factors. 
From the compilation of this comprehensive information, we developed 
the Aging Transport Non-Structural Systems Plan to increase airplane 
safety by increasing knowledge of how non-structural systems degrade 
and how causes of degradation can be reduced.
    In 1998, an accident occurred off the coast of Nova Scotia 
involving a McDonnell Douglas Model MD-11 series airplane. 
Investigation indicates that a fire broke out in the cockpit and first 
class overhead area. Although the ignition source of the fire has not 
been determined, the FAA, in conjunction with Boeing and operators of 
Model MD-11, DC-8, DC-9, DC-10, and DC-9-80 series airplanes, is 
reviewing all aspects of the service history of those airplanes to 
identify potential unsafe conditions associated with wire degradation 
due to various contributing factors (e.g., inadequate maintenance, 
contamination, improper repair, and mechanical damage) and to take 
appropriate corrective actions. We have issued a series of 
airworthiness directives (AD) that address unsafe conditions identified 
during that process. This process is continuing and we may consider 
additional rulemaking actions as further results of the review become 
available. The cause of the Nova Scotia MD-11 accident has not yet been 
determined.
    In 1999, the FAA Administrator established a formal advisory 
committee to facilitate the implementation of the Aging Transport Non-
Structural Systems Plan. This committee, the Aging Transport Systems 
Rulemaking Advisory Committee (ATSRAC), is made up of representatives 
of airplane manufacturers, operators, user groups, aerospace and 
industry associations, and government agencies. As part of its mandate, 
ATSRAC will recommend rulemaking to increase transport category 
airplane safety in cases where solutions to safety problems connected 
to aging systems have been found and must be applied. Detailed analyses 
of certain transport category airplanes that have been removed from 
service, studies of service bulletins pertaining to certain wiring 
systems, and reviews of previously issued airworthiness directives (AD) 
requiring repetitive inspections of certain wiring systems, have 
resulted in valuable information on the cause and prevention of wire 
degradation due to various contributing factors (e.g., inadequate 
maintenance, contamination, improper repair, and mechanical damage).
    In summary, as a result of the investigations described above, the 
FAA has determined that corrective action may be necessary to minimize 
the potential hazards associated with wire degradation. Such corrective 
action can be addressed in future ADs to provide an acceptable level of 
safety for the transport airplane fleet.

Identification of Unsafe Condition

    The FAA has become aware of incidents in which the electrical bus 
of the auxiliary power unit (APU) failed on McDonnell Douglas Model DC-
9 series airplanes. Investigation revealed that these failures were due 
to overheated wires at a terminal strip as a result of loose terminal 
stud connections and consequent damaged copper terminals. A 
contributing factor to the loose terminal stud connections in this 
installation may be a ``cold flow'' phenomenon, which takes place when 
aluminum terminals expand during high electrical current flow and 
contract when current is reduced. Loose terminal stud connections 
require tightening, which can damage the copper terminals and cause 
overheating of the terminal strip wires. Such overheating could result 
in electrical failure, which could result in smoke and fire in the 
electrical/electronic (E/E) compartment.

Other Related Rulemaking

    This proposed AD is one of a series of actions identified as part 
of the ATSRAC program initiative to maintain continued operational 
safety of aging non-structural systems in transport category airplanes. 
The program is continuing and the FAA may consider additional 
rulemaking actions as further results of the review become available.

Explanation of Relevant Service Information

    The FAA has reviewed and approved McDonnell Douglas Alert Service 
Bulletin DC9-24A072, Revision 01, dated May 22, 2000. The service 
bulletin describes procedures for a general visual inspection of the 
power feeder bus cables of the APU for overheat damage between fuselage 
stations Y=160.000 (Item No. S3-287) and Y=148.000 (Item No. S3-23); 
and corrective action(s), if necessary. The corrective actions involve 
revising the wiring installation; repairing or replacing wiring with 
new wiring; and replacing the nameplate with a new nameplate; as 
applicable. Accomplishment of the actions specified in the service 
bulletin is intended to adequately address the identified unsafe 
condition.

[[Page 38172]]

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 bulletin described previously.

Cost Impact

    There are approximately 550 Model DC-9-10, -20, -30, -40, and -50 
series airplanes; C-9 (military) airplanes; Model DC-9-81, -82, -83, 
and -87 series airplanes; and Model MD-88 airplanes of the affected 
design in the worldwide fleet. The FAA estimates that 450 airplanes of 
U.S. registry would be affected by this proposed AD, that it would take 
approximately 1 work hour per airplane to accomplish the proposed 
inspection, and that the average labor rate is $60 per work hour. Based 
on these figures, the cost impact of the proposed AD on U.S. operators 
is estimated to be $27,000, or $60 per airplane.
    The cost impact figure discussed above is 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 proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.

Regulatory Impact

    The regulations proposed herein would not have a substantial direct 
effect 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, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    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:

    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-291-AD.

    Applicability: Model DC-9-10, -20, -30, -40, and -50 series 
airplanes; C-9 (military) airplanes; Model DC-9-81, -82, -83, and -
87 series airplanes; and Model MD-88 airplanes; as listed in 
McDonnell Douglas Alert Service Bulletin DC9-24A072, Revision 01, 
dated May 22, 2000; 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) 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 electrical failure due to overheated wires at the 
terminal strip, which could result in smoke and fire in the 
electrical/electronic compartment, accomplish the following:

General Visual Inspection

    (a) Within 1 year after the effective date of this AD, do a 
general visual inspection of the power feeder bus cables of the 
auxiliary power unit (APU) for overheat damage between fuselage 
stations Y=160.000 (Item No. S3-287) and Y=148.000 (Item No. S3-23), 
per McDonnell Douglas Alert Service Bulletin DC9-24A072, Revision 
01, dated May 22, 2000.

    Note 2: For the purposes of this AD, a general visual inspection 
is defined as ``A visual examination of an interior or exterior 
area, installation, or assembly to detect obvious damage, failure, 
or irregularity. This level of inspection is made under normally 
available lighting conditions such as daylight, hangar lighting, 
flashlight, or drop-light, and may require removal or opening of 
access panels or doors. Stands, ladders, or platforms may be 
required to gain proximity to the area being checked.''

Condition 1 (No Evidence of Damage)

    (b) If no damage is detected during the inspection required by 
paragraph (a) of this AD, do the applicable action specified in 
paragraph (b)(1) or (b)(2) of Table 1 of this AD, per McDonnell 
Douglas Alert Service Bulletin DC9-24A072, Revision 01, dated May 
22, 2000. Table 1 is as follows:

                         Table 1.--Condition 1.
------------------------------------------------------------------------
 For airplanes identified in the
referenced service bulletin as .        Action                By
               . .
------------------------------------------------------------------------
(1) Group 1.....................  Revise the wiring   Before further
                                   installation and    flight.
                                   replace the
                                   nameplate with a
                                   new nameplate.
------------------------------------------------------------------------
(2) Group 2.....................  Revise the wiring   Before further
                                   installation.       flight.
------------------------------------------------------------------------
(3) Group 3.....................  No further action   [Reserved]
                                   is required by
                                   this AD.
------------------------------------------------------------------------


[[Page 38173]]

Condition 2 (Evidence of Damage)

    (c) If any damage is detected during the inspection required by 
paragraph (a) of this AD, do the applicable action(s) specified in 
paragraph (c)(1), (c)(2), or (c)(3) of Table 2 of this AD, per 
McDonnell Douglas Alert Service Bulletin DC9-24A072, Revision 01, 
dated May 22, 2000. Table 2 is as follows:

                         Table 2.--Condition 2.
------------------------------------------------------------------------
 For airplanes identified in the
referenced service bulletin as .        Action                By
               . .
------------------------------------------------------------------------
(1) Group 1.....................  (i) Repair or       Before further
                                   replace wiring      flight.
                                   with new wiring;
                                   and.
                                 ---------------------------------------
                                  (ii) Revise wiring  Before further
                                   installation; and.  flight.
                                 ---------------------------------------
                                  (iii) Replace       Before further
                                   nameplate with a    flight.
                                   new nameplate.
------------------------------------------------------------------------
(2) Group 2.....................  (i) Repair or       Before further
                                   replace wiring      flight.
                                   with new wiring;
                                   and.
                                 ---------------------------------------
                                  (ii) Revise wiring  Before further
                                   installation.       flight.
------------------------------------------------------------------------
(3) Group 3.....................  (i) Repair wiring,  Before further
                                   or.                 flight.
                                 ---------------------------------------
                                  (ii) Replace        Before further
                                   wiring with new     flight.
                                   wiring.
------------------------------------------------------------------------

Alternative Methods of Compliance

    (d) 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. 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 3: 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 Permit

    (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.

    Issued in Renton, Washington, on July 9, 2001.

Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-17585 Filed 7-20-01; 8:45 am]
BILLING CODE 4910-13-U