[Federal Register Volume 62, Number 227 (Tuesday, November 25, 1997)]
[Proposed Rules]
[Pages 62726-62728]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-30868]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-138-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-400 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.


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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 747-400 
series airplanes. This proposal would require removal and 
reconfiguration of the battery grounds of the auxiliary power unit 
(APU). This proposal is prompted by reports of smoke or fire coming 
from the APU due to battery grounds that were not installed or 
maintained properly. The actions specified by the proposed AD are 
intended to prevent overheating and heat damage of the APU battery 
grounds due to improper installation of the APU battery ground, which 
could result in heat damage and consequent smoke or fire on the 
airplane.

DATES: Comments must be received by January 9, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-138-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 Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207.
    This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Forrest Keller, Senior Aerospace 
Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington; 
telephone (425) 227-2790; fax (425) 227-1181.

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 97-NM-138-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-103, Attention: Rules 
Docket No. 97-NM-138-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports of smoke or fire during ground 
operation and after auxiliary power unit (APU) start that occurred 
below the APU battery ground on certain Boeing Model 767 series 
airplanes. Investigation revealed that the APU, which has a pre-
installed, single-ground, single-lug configuration, was the possible 
source of ignition; fuel for the fire was attributed to debris in the 
area. Further investigation revealed that an APU battery ground wire 
connection was loose and the torque of the nut (less than 140 inch-
pounds) was less than the minimum (180 inch-pounds) necessary for the 
ground configuration. The APU battery ground showed signs of arcing and 
did not have the two washers necessary for the ground build-up. Such 
improper installation or maintenance, if not corrected, could result in 
heat damage to the battery grounds of the APU and consequent smoke or 
fire on the airplane.

Related AD's

    On July 11, 1997, the FAA issued AD 97-15-09, amendment 39-10083 
(62 FR 38204, July 17, 1997), applicable to all Boeing Model 757 and 
767 series airplanes. That AD requires repetitive inspections to detect 
damage and to verify proper configuration of the battery ground 
terminations of the APU at the battery and connected structure; and 
removal, replacement, and repair of the battery ground termination, if 
necessary. That AD was prompted by reports of smoke or fire coming from 
the APU due to battery grounds that were not installed or maintained 
properly.

Similar Model Subject to the Unsafe Condition

    APU battery ground configurations installed on Boeing Model 757 and 
767 series airplanes are similar to those APU battery grounds installed 
on Boeing Model 747-400 series airplanes; therefore, Model 747-400 
series airplanes may be subject to the same unsafe condition described 
previously.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-24A2214, dated June 19, 1997, which describes procedures for 
reconfiguring the APU battery grounds from a single-ground, single-lug 
configuration to a dual-direct ground, single-lug configuration. This 
new configuration has less mounting hardware and a larger electrical 
bonding surface area, which will prevent overheating of the APU battery 
ground due to improper installation of the APU battery grounds.

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 reconfiguring the APU battery grounds from a 
single-ground, single-lug configuration to a dual-direct ground, 
single-lug configuration. The actions would be required to be 
accomplished in accordance with the alert service bulletin described 
previously.

Cost Impact

    There are approximately 359 Model 747-400 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 26 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 16 work hours per airplane to accomplish 
the proposed actions, and that the average labor rate is $60 per work 
hour. Required parts would cost approximately $1,325 per airplane. 
Based on these figures, the cost impact of the proposed AD on U.S. 
operators is estimated to be $59,410, or $2,285 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 AD were not adopted.

[[Page 62728]]

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:

    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 97-NM-138-AD. Applicability: Model 747-400 series 
airplanes; as listed in Boeing Alert Service Bulletin 747-24A2214, 
dated June 19, 1997; certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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 (b) 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 the auxiliary power unit (APU) from overheat and heat 
damage due to an improperly installed/maintained APU battery ground, 
accomplish the following:
    (a) Within 6 months after the effective date of this AD, 
reconfigure the APU battery grounds to a dual-direct ground, single-
lug configuration, in accordance with Boeing Alert Service Bulletin 
747-24A2214, dated June 19, 1997.
    (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, Seattle 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, 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.

    (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.

    Issued in Renton, Washington, on November 18, 1997.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-30868 Filed 11-24-97; 8:45 am]
BILLING CODE 4910-13-P