[Federal Register Volume 64, Number 226 (Wednesday, November 24, 1999)]
[Proposed Rules]
[Pages 66118-66119]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-30630]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NE-25-AD]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan
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 Pratt & Whitney JT9D
series turbofan engines. This proposal would require installation of an
improved No. 4 bearing internal oil pressure tube, initial and
repetitive inspections of the No. 4 bearing oil pressure tube for
turbine exhaust case (TEC) strut clearance and alignment, and, if
necessary, replacement with serviceable parts. This proposal is
prompted by loss of integrity in the oil system, which allows oil to
migrate into high temperature metal cavities in the turbine exhaust
case and cause oil fires. The actions specified by the proposed AD are
intended to prevent oil fires in and around the No. 4 bearing area,
which could result in excessive growth of the sixth stage low pressure
turbine (LPT) disk, liberation of the sixth stage LPT disk, uncontained
engine failure, and damage to the airplane.
DATES: Comments must be received by January 24, 2000.
ADDRESSES: Submit comments to the Federal Aviation Administration
(FAA), New England Region, Office of the Regional Counsel, Attention:
Rules Docket No. 99-NE-25-AD, 12 New England Executive Park,
Burlington, MA 01803-5299. Comments may also be sent via the Internet
using the following address: ``[email protected]''. Comments sent
via the Internet must contain the docket number in the subject line.
Comments may be inspected at this location between 8:00 a.m. and 4:30
p.m., Monday through Friday, except Federal holidays.
The service information referenced in the proposed rule may be
obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108;
telephone (860) 565-6600, fax (860) 565-4503. This information may be
examined at the FAA, New England Region, Office of the Regional
Counsel, 12 New England Executive Park, Burlington, MA.
FOR FURTHER INFORMATION CONTACT: Chris Gavriel, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; telephone (781)
238-7147, fax (781) 238-7199.
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 should identify the Rules Docket number
and be submitted 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 99-NE-25-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, New England Region, Office of the Regional Counsel,
Attention: Rules Docket No. 99-NE-25-AD, 12 New England Executive Park,
Burlington, MA 01803-5299.
Discussion
The Federal Aviation Administration (FAA) has received reports of
oil fires in and around the No. 4 bearing area on Pratt & Whitney (PW)
JT9D series turbofan engines. The investigation revealed that the oil
fires were caused by loss of integrity in the oil system, which allows
oil to migrate into high temperature metal cavities in the turbine
exhaust case (TEC) and cause oil fires. The heat generated by the fire
can cause excessive growth of the sixth stage low pressure turbine
(LPT) disk. This condition, if not corrected, could result in oil fires
in and around the No. 4 bearing area, which could result in excessive
growth due to heat of the sixth stage low pressure turbine (LPT) disk,
liberation of the sixth stage LPT disk, uncontained engine failure, and
damage to the airplane.
Service Information
The FAA has reviewed and approved the technical contents of PW
Service Bulletins (SB) No. 5707, dated September 17, 1986, and JT9D-
7R4-72-289, dated March 26, 1986, that describe procedures for
installation of an improved No. 4 bearing internal oil pressure tube;
and PW JT9D Engine Manuals, part numbers (P/Ns) 646028, 777210, 754459,
and 785059, that describe TEC inspection procedures.
Proposed Actions
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 an improved No. 4 bearing
internal oil pressure tube, initial and repetitive inspections of the
No. 4 bearing oil pressure tube for TEC strut clearance and alignment,
and, if necessary, replacement with serviceable
[[Page 66119]]
parts. The actions would be required to be accomplished in accordance
with the SB described previously and in accordance with certain
sections of the engine manuals.
Economic Analysis
There are approximately 2,310 engines of the affected design in the
worldwide fleet. The FAA estimates that (1) 1,183 engines installed on
airplanes of U.S. registry would be affected by this proposed AD, (2)
it would take approximately 1 work hour per engine to accomplish the
proposed actions, and (3) the average labor rate is $60 per work hour.
Required parts would cost approximately $1,465 per engine. Review of
purchase order documents indicate that approximately 1,547 pressure
tubes have been sold to the airlines; therefore this action would
affect only 763 engines. Based on these figures, the total cost impact
of the proposed AD on U.S. operators is estimated to be $1,163,575.
Regulatory Impact
This proposal does not have federalism implications, as defined in
Executive Order No. 13132, because it 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. Accordingly,
the FAA has not consulted with state authorities prior to publication
of this proposal.
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:
Pratt & Whitney: Docket No. 99-NE-25-AD.
Applicability: Pratt & Whitney (PW) JT9D-3A, -7, -7A, -7AH, -7H,
-7F, -7J, -7Q, -7Q3, -20, -20J, -59A, -70A, and -7R4D series
turbofan engines, installed on but not limited to Boeing 747 and 767
and McDonnell Douglas DC-10 series aircraft.
Note 1: This airworthiness directive (AD) applies to each engine
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 engines 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 oil fires in and around the No. 4 bearing area, which
could result in excessive growth due to heat of the sixth stage low
pressure turbine (LPT) disk, liberation of the sixth stage LPT disk,
uncontained engine failure, and damage to the airplane, accomplish
the following:
Installation of Improved Hardware
(a) At the next time when the ``N'' or ``P'' flange is
disconnected after the effective date of this AD, install an
improved No. 4 bearing internal oil pressure tube in accordance with
PW Service Bulletin (SB) No. 5707, dated September 17, 1986, and SB
JT9D-7R4-72-289, dated March 26, 1986.
Inspections
(b) Perform initial and repetitive inspections of the No. 4
bearing oil pressure tube and turbine exhaust case (TEC) strut for
clearance and alignment, and, if necessary, replace with serviceable
parts, in accordance with the applicable PW JT9D Engine Manuals,
part numbers (P/Ns) 646028, 777210, and 754459, Turbine Exhaust Case
Inspection 01, Section 72-53-01, and P/N 785059, Turbine Exhaust
Case Inspection 01, Section 72-53-05, as follows:
(1) Initially inspect at the next time when the ``N'' or ``P''
flange is disconnected after the effective date of this AD.
(2) Thereafter, inspect at each time when the ``N'' or ``P''
flange is disconnected.
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, Engine Certification Office.
Operators shall submit their request through an appropriate FAA
Principal Maintenance Inspector, who may add comments and then send
it to the Manager, Engine Certification Office.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this airworthiness directive,
if any, may be obtained from the Engine Certification Office.
Ferry Flights
(d) Special flight permits may be issued in accordance with
sections Secs. 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 Burlington, Massachusetts, on October 18, 1999.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 99-30630 Filed 11-23-99; 8:45 am]
BILLING CODE 4910-13-U