[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]
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