[Federal Register Volume 67, Number 154 (Friday, August 9, 2002)]
[Proposed Rules]
[Pages 51785-51787]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-20132]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-291-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-600, -700, -700C, -
800, and -900 Series Airplanes Equipped With Honeywell Start Converter 
Units

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 Boeing Model 737-600, -
700, -700C, -800, and -900 series airplanes equipped with certain 
Honeywell start converter units (SCU). This proposal would require 
replacement of the SCU of the auxiliary power unit (APU) located in the 
electrical and electronics (E/E) compartment with a new, improved SCU. 
This action is necessary to prevent overheating of the electrical 
connector of the SCU, which could create an ignition source and 
possible fire in the E/E compartment and cause damage to certain 
electrical wire bundles on the E2-2 shelf. Such damage could result in 
loss of power from the APU generator, failure of electrically powered 
airplane systems, and consequent reduction in the ability of the flight 
crew to control the airplane in certain adverse operating conditions. 
This action is intended to address the identified unsafe condition.

DATES: Comments must be received by September 23, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-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. 2001-NM-291-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronics files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    Information pertaining to this amendment may be obtained from or 
examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, 
SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Stephen S. Oshiro, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 227-2793; fax (425) 227-1181.

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.
     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 2001-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. 2001-NM-291-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received several reports of failure of the auxiliary 
power unit (APU) to start or to generate electrical power after start-
up or during APU operation on certain Boeing Model 737-700 and -800 
series airplanes. During these APU failures, there was an odor of smoke 
detected by personnel on the flight deck. Investigation revealed signs 
of heat damage to the Aeronautical Radio, Incorporated (ARINC), 
connector of the APU start converter unit (SCU). (The ARINC connector 
is located on the back panel of the SCU housing and provides for 
electrical connection between the SCU and the APU generator.) The heat 
damage spread to the mating connector and adjacent wire bundles located 
on the E2-2 shelf of the electrical and electronics (E/E) compartment. 
Further investigation revealed that the damage was caused by a short 
circuit of certain capacitors that are part of the electromagnetic 
interference filter inside the ARINC connector. Such conditions, if not 
corrected, could result in overheating of the electrical connector of 
the SCU, which could create an ignition source and possible fire in the 
E/E compartment and cause damage to certain electrical wire bundles on 
the E2-2 shelf. Such damage could result in loss of power from the APU 
generator, failure of electrically powered airplane systems, and 
consequent reduction in the ability of the flight crew to control the 
airplane in certain adverse operating conditions.
    The SCU of the APU is the same on certain Model 737-600 and -900 
series airplanes as it is on certain Model 737-700, -700C, and -800 
series airplanes. Therefore, all of these airplanes may be subject to 
the same unsafe condition described above.

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 is being issued to prevent overheating of the electrical 
connector of the SCU, which could create an ignition source and 
possible fire in the E/E compartment and cause damage to certain 
electrical wire bundles on the E2-2 shelf. Such

[[Page 51786]]

damage could result in loss of power from the APU generator, failure of 
electrically powered airplane systems, and consequent reduction in the 
ability of the flight crew to control the airplane in certain adverse 
operating conditions. The proposed AD would require replacement of 
certain SCUs with new, improved SCUs. The SCUs would be required to be 
replaced according to Boeing 737-600/700/800/900 Airplane Maintenance 
Manual (AMM)(the AMM includes procedures for Model 737-700C series 
airplanes).

Cost Impact

    There are approximately 901 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 441 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
4 work hours per airplane to accomplish the proposed actions, and that 
the average labor rate is $60 per work hour. Required parts would be 
provided by the parts manufacturer at no cost to operators. Based on 
these figures, the cost impact of the proposed AD on U.S. operators is 
estimated to be $105,840, or $240 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:
Boeing: Docket 2001-NM-291-AD.

    Applicability: Model 737-600, -700, -700C, -800, and -900 series 
airplanes; certificated in any category; equipped with start 
converter units (SCUs) having Honeywell part number (P/N) 1151858-
241, Series 1 through 9 inclusive, or 
P/N 1152426-245, Series 1 through 6 inclusive.

    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 overheating of the electrical connector of the SCU, 
which could create an ignition source and possible fire in the 
electrical and electronics (E/E) compartment and cause damage to 
certain electrical wire bundles on the E2-2 shelf, accomplish the 
following:

Replacement

    (a) Within 18 months after the effective date of this AD: 
Replace the SCU of the auxiliary power unit located in the E/E 
compartment, according to Boeing 737-600/700/800/900 Airplane 
Maintenance Manual, Chapter 49-41-61, dated June 5, 1998. Replace 
the applicable SCU listed in the ``Existing Honeywell P/N'' column 
below, with the corresponding SCU listed in the ``Replacement 
Honeywell P/N'' column below, as follows:

SCU Part Numbers

------------------------------------------------------------------------
       Existing Honeywell P/N             Replacement Honeywell P/N
------------------------------------------------------------------------
1151858-241, Series 1..............  1151858-241, Series 10.
1151858-241, Series 2..............  1151858-241, Series 11.
1151858-241, Series 3..............  1151858-241, Series 12.
1151858-241, Series 4..............  1151858-241, Series 10.
1151858-241, Series 5..............  1151858-241, Series 11.
1151858-241, Series 6..............  1151858-241, Series 12.
1151858-241, Series 7..............  1151858-241, Series 10.
1151858-241, Series 8..............  1151858-241, Series 11.

[[Page 51787]]

 
1151858-241, Series 9..............  1151858-241, Series 12.
1152426-245, Series 1..............  1152426-245, Series 7.
1152426-245, Series 2..............  1152426-245, Series 8.
1152426-245, Series 3..............  1152426-245, Series 7.
1152426-245, Series 4..............  1152426-245, Series 8.
1152426-245, Series 5..............  1152426-245, Series 7.
1152426-245, Series 6..............  1152426-245, Series 8
------------------------------------------------------------------------

Spares

    (b) As of the effective date of this AD, no person shall install 
on any airplane an SCU having P/N 1151858-241, Series 1 through 9 
inclusive, or P/N 1152426-245, Series 1 through 6 inclusive.

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, Seattle 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, Seattle ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permit

    (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 July 29, 2002.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-20132 Filed 8-8-02; 8:45 am]
BILLING CODE 4910-13-P