[Federal Register Volume 60, Number 238 (Tuesday, December 12, 1995)]
[Proposed Rules]
[Pages 63663-63665]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-30213]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-98-AD]


Airworthiness Directives; Boeing Model 747-400 Series Airplanes 
Powered by General Electric CF6-80C2 or Pratt & Whitney PW4000 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 747-400 
series airplanes. This proposal would require modification of the 
engine fuel feed system. This proposal is prompted by reports 
indicating that the coupling nut on the fuel tube on the outboard strut 
(engine position 1) fractured. The actions specified by the proposed AD 
are intended to prevent such fracturing of the coupling nut, which 
could result in release of fuel onto the engine cowling and a 
subsequent fire.


[[Page 63664]]

DATES: Comments must be received by February 6, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-98-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: Tamra J. Elkins, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington; telephone (206) 227-
2669; 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 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 95-NM-98-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. 95-NM-98-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056

Discussion

    The FAA has received reports indicating that the coupling nut on 
the fuel tube on the outboard strut (engine position 1) on several 
Boeing Model 747-400 series airplanes fractured. Fracturing of the 
coupling nut caused fuel to leak onto the engine cowling. This 
fracturing has been attributed to relative movement between the 
outboard struts (engine positions 1 and 4) and the wing front spar. 
Fracturing of the coupling nut on the fuel tube can result in release 
of fuel onto the engine cowling. This condition, if not corrected, 
could result in a fire.
    The FAA has reviewed and approved two service bulletins that 
describe procedures for modification of the engine fuel feed system:
    1. Boeing Alert Service Bulletin 747-28A2185, Revision 1, dated 
September 21, 1995, which applies to certain Model 747-400 series 
airplanes powered by either General Electric CF6-80C2 or Pratt & 
Whitney PW4000 series engines. This service bulletin describes 
procedures for replacement of the strut fuel tubes and couplings at 
engine positions 1 and 4. The replacement involves installing new 
shrouded couplings that have been redesigned to be more flexible in 
response to the relative movement between the outboard struts and the 
wing front spar.
    2. Boeing Service Bulletin 747-28-2146, dated August 13, 1992, 
which applies to certain Model 747-400 series airplanes powered by 
General Electric CF6-80C2 series engines. This service bulletin 
describes procedures for installation of new fuel lines, shrouded fuel 
line couplings redesigned to be more flexible (between the strut mid 
bulkhead and the wing front spar), and drain lines at each engine 
position to provide a drain path from the new couplings to the existing 
drain system.
    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 modification of the engine fuel feed system. 
The actions would be required to be accomplished in accordance with the 
service bulletins described previously.
    Operators should note that, although Boeing Service Bulletin 747-
28-2146 recommends installation of fuel lines, couplings, and drain 
lines at each engine position, this proposed AD would require those 
installations only at engine positions 1 and 4. The FAA finds that the 
addressed unsafe condition does not exist with regard to engine 
positions 2 and 3, since relative movement between those engine 
positions and the wing front spar is insufficient to cause fracturing 
of the coupling nut. Further, the FAA has received no reports of 
fracturing of the coupling nut that have been attributed to relative 
movement between engine positions 2 and 3 and the wing front spar.
    There are approximately 226 Model 747-400 series airplanes of the 
affected design in the worldwide fleet.
    The FAA estimates that 34 airplanes of U.S. registry would be 
required by this proposed AD to replace the strut fuel tubes and 
couplings at engine positions 1 and 4 in accordance with Boeing Alert 
Service Bulletin 747-28A2185. That replacement would take approximately 
74 work hours per airplane to accomplish, at an average labor rate of 
$60 per work hour. Required parts would cost approximately $9,582 per 
airplane. Based on these figures, the cost impact of this proposed 
replacement on U.S. operators is estimated to be $476,748, or $14,022 
per airplane.
    Currently, there are no Model 747-400 series airplanes on the U.S. 
Register that would be required by this AD to accomplish the 
installation specified in Boeing Service Bulletin 747-28-2146. However, 
should an affected airplane be imported and placed on the U.S. Register 
in the future, it would require approximately 162 work hours per 
airplane (81 work hours per engine; 2 engines per airplane) to 
accomplish the proposed installation, at an average labor rate of $60 
per work hour. Required parts would cost approximately $9,582 per 
airplane. Based on these figures, the cost impact of this proposed 
installation would be $19,302 per airplane.
    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 

[[Page 63665]]
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 USC 106(g), 40101, 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: Docket 95-NM-98-AD.

    Applicability: Model 747-400 series airplanes powered by General 
Electric CF6-80C2 or Pratt & Whitney PW4000 series engines; as 
identified in Boeing Alert Service Bulletin 747-28A2185, Revision 1, 
dated September 21, 1995, and Boeing Service Bulletin 747-28-2146, 
dated August 13, 1992; 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 use the authority 
provided in paragraph (b) of this AD to request approval from the 
FAA. This approval may address either no action, if the current 
configuration eliminates the unsafe condition; or different actions 
necessary to address the unsafe condition described in this AD. Such 
a request should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent fracturing of the coupling nut, which could result in 
release of fuel onto the engine cowling and a subsequent fire, 
accomplish the following:
    (a) Within 18 months after the effective date of this AD, 
accomplish the requirements of paragraph (a)(1) or (a)(2), as 
applicable.
    (1) For Model 747-400 series airplanes identified in Boeing 
Alert Service Bulletin 747-28A2185, Revision 1, dated September 21, 
1995: Replace the strut fuel tubes and couplings at engine numbers 1 
and 4 with new redesigned (shrouded) couplings, in accordance with 
that alert service bulletin.
    (2) For Model 747-400 series airplanes having variable numbers 
RT641 through RT650 inclusive, identified in Boeing Service Bulletin 
747-28-2146, dated August 13, 1992: On engine positions 1 and 4 
only, install new fuel lines, shrouded fuel line couplings (between 
the strut mid bulkhead and the wing front spar), and drain lines in 
accordance with that service bulletin.
    (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 December 6, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-30213 Filed 12-11-95; 8:45 am]
BILLING CODE 4910-13-U