Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan Engines

[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: ``9-ane-adcomment@faa.gov''. 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