[Federal Register Volume 59, Number 110 (Thursday, June 9, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-14019]


[[Page Unknown]]

[Federal Register: June 9, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-52-AD]

 

Airworthiness Directives; Boeing Model 747 Series Airplanes 
Equipped With General Electric CF6-45 or CF6-50 Engines or Pratt & 
Whitney JT9D Series Engines

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 747 series 
airplanes. This proposal would require installation of a seal on the 
wing front spar at each engine strut. This proposal is prompted by a 
report of a fire that occurred due to fuel leakage from the fuel line 
coupling in the engine strut area along with the wing front spar while 
the airplane was on the ground after engine shutdown. The actions 
specified by the proposed AD are intended to ensure that fuel is 
contained within the strut drainage area and channeled away from 
ignition sources.

DATES: Comments must be received by August 3, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-52-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.
    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:
G. Michael Collins, Aerospace Engineer, Propulsion Branch, ANM-140S, 
FAA, Transport Airplane Directorate, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(206) 227-2689; fax (206) 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 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 proposal 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 94-NM-52-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. 94-NM-52-AD, 1601 Lind Avenue SW., Renton, Washington 98055-
4056.

Discussion

    The FAA has received a report of a strut fire that occurred due to 
fuel leakage from the fuel line (Wiggins) coupling in the engine strut 
area of a Boeing Model 747 series airplane that was on the ground. Fuel 
leaked from the fuel line coupling and flowed along the wing front 
spar. After engine shutdown, fuel dripped from the wing onto the engine 
exhaust section and ignited. The flame also ignited fuel that was 
contained in the strut. This condition, if not corrected, could result 
in a strut fire.
    Although airflow when the airplane is in flight or airflow from the 
engine running when the airplane is on the ground prevents fuel from 
leaking onto hot engine surfaces, the FAA has determined that a 
potential unsafe condition exists because a fire can occur after engine 
shutdown.
    The FAA has reviewed and approved Boeing Service Bulletin 747-28-
2160, Revision 1, dated December 16, 1993, that describes procedures 
for installing a seal on the wing front spar at each engine strut. 
Installation of this seal will contain fuel leaks within the strut 
drainage area and channel any leakage away from ignition sources.
    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 installation of a seal on the wing front spar 
at each engine strut. The actions would be required to be accomplished 
in accordance with the service bulletin described previously.
    There are approximately 610 Boeing Model 747 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 183 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 14 work hours per airplane to accomplish 
the proposed actions, and that the average labor rate is $55 per work 
hour. Required parts would cost approximately $57 per airplane. Based 
on these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $151,341, or $827 per airplane.
    The total 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.
    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 14 
CFR part 39 of the Federal Aviation Regulations 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:

Boeing: Docket 94-NM-52-AD.

    Applicability: Model 747 series airplanes, equipped with General 
Electric CF6-45 or CF6-50 engines, or Pratt & Whitney JT9D series 
engines; as listed in Boeing Service Bulletin 747-28-2160, Revision 
1, dated December 16, 1993; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To ensure that fuel is contained within the strut drainage area 
and channeled away from ignition sources, accomplish the following:
    (a) Within 12 months after the effective date of this AD, 
install a seal on the wing front spar at each engine strut in 
accordance with Boeing Service Bulletin 747-28-2160 dated July 23, 
1992, or Revision 1, dated December 16, 1993.
    (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: 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 June 3, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-14019 Filed 6-8-94; 8:45 am]
BILLING CODE 4910-13-M