AD 2000-23-14

[Federal Register Volume 65, Number 224 (Monday, November 20, 2000)]
[Rules and Regulations]
[Pages 69660-69662]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 00-29212]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-25-AD; Amendment 39-11986; AD 2000-23-14]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Pratt & Whitney JT9D series turbofan engines. 
This AD will 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 amendment is prompted by loss of integrity in 
the oil system that allows oil to migrate into high temperature metal 
cavities in the turbine exhaust case and cause oil fires. The actions 
specified by this AD are intended to prevent oil fires in and around 
the No. 4 bearing area that could cause excessive thermal 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: Effective date January 19, 2001. The incorporation by reference 
of certain publications listed in the rule is approved by the Director 
of the Federal Register as of January 19, 2001.

ADDRESSES: The service information referenced in this AD may be 
obtained from Pratt & Whitney, 400 Main Street, East Hartford, CT 
06108; telephone: (860) 565-6600, fax: (860) 565-4503. This information 
may be examined at the Federal Aviation Administration (FAA), New 
England Region, Office of the Regional Counsel, 12 New England 
Executive Park, Burlington, MA; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) applicable to Pratt & Whitney (PW) JT9D series turbofan 
engines was published in the Federal Register on November 24, 1999 (64 
FR 66118). That action proposed to 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 parts, in accordance with PW Service Bulletin (SB) No. 
5707, dated September 17, 1986, and in accordance with certain sections 
of the PW JT9D Engine Manuals: part numbers (P/Ns) 646028, 770407, 
770408, 777210, 785059, and 754459.

[[Page 69661]]

Comments Received

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Reasons for This Modification and Inspection Program

    One commenter states that the reports referenced in the NPRM focus 
only on engine fires, not uncontained engine failure and aircraft 
damage. Since the commenter has been using a tube of a design earlier 
to the one required by this AD for a long time without incident, the 
commenter requests that the FAA confirm the reasons for the 
modification and inspection program.
    The FAA investigated the reports of oil fires in and around the No. 
4 bearing area on the PW JT9D series turbofan engines and concluded 
that the heat generated by the oil fires could cause excessive thermal 
growth of the sixth stage LPT disk, liberation of the sixth stage LPT 
disk, uncontained engine failure, and damage to the airplane.

Applicability Section

    One commenter requests the modification of the applicability 
section of the AD to specify the BG 700 series of the JT9D-7R4D 
engines. The applicability section of the NPRM includes the JT9D-7R4D 
series engines. The PW SB JT9D-7R4-72-289, dated March 26, 1986, 
applies to the BG 700 series. The commenter has the JT9D-7R4D (BG 900) 
series engines and would like the applicability section of the AD to 
reflect the BG 700 series.
    The FAA agrees. The applicability section has been changed 
accordingly. Another commenter requests that the list of aircraft on 
which the affected engines may be installed be expanded to include 
Airbus A300 airplanes. The FAA agrees. The FAA will add Airbus A300 
airplanes to the list, but cautions that this AD list is advisory in 
nature and does not limit the applicability of the AD to just those 
engines which are installed on the listed airplanes.

Engine Manual Part Numbers

    One commenter requests that paragraph (b) reflect the JT9D-7A 
engine manual P/N 770408. The commenter also requests that the section 
title of 72-53-01 of the JT9D-59A engine manual, P/N 754459, be revised 
to reflect ``Heavy Maintenance Check'' instead of ``Inspection 01.''
    The FAA agrees. The engine manual P/Ns listed in the NPRM contain 
all engine models affected. However, the engine manufacturer has issued 
model-specific versions of these manuals. Therefore, it is possible 
that the operator may only have the model-specific version of the 
manual and not the all-encompassing engine manuals referred to in this 
AD. Revised paragraph (b) includes references to the model-specific 
JT9D engine manuals and to correct the reference to the title of 
Section 72-53-01 of P/N 754459.

Inspection Interval

    Another commenter requests that the FAA weigh the benefits of 
conducting frequent inspections against the additional risks incurred 
by conducting the inspections. The commenter also states that it has 
not experienced an oil pressure tube failure due to TEC strut 
misalignment. The commenter considers an inspection interval at each 
heavy engine shop visit to be adequate, as opposed to every time the 
``N'' or ``P'' flange is separated.
    Two commenters recommend that the FAA replace the word 
``disconnected'' with the word ``separated.'' The phrase ``at the next 
time when the ``N'' or ``P'' flange is disconnected'' occurs three 
times in the AD. One of the commenters suggests that since a flange is 
normally separated, not disconnected, this language may cause some 
confusion.
    The FAA agrees in part. The FAA has decided to change the 
definition of shop visit to better reflect the original intent of the 
inspection. The original intent was that the inspections be performed 
during a complete disassembly of the TEC; this is the frequency 
interval contained in the engine manuals. The proposed language even if 
the recommended change from ``disconnected'' to ``separated'' is made, 
could still be perceived as a more frequent inspection interval than 
that intended by the FAA. Based on comments received and further 
coordination with the engine manufacturer, the FAA has developed a more 
precise definition. Therefore, the FAA has revised the phrase, ``at the 
next time when the ``N'' or ``P'' flange is disconnected,'' to read: 
``at the next turbine exhaust case disassembly when all hardware is 
stripped from the case.'' These inspections are required at the same 
frequency contained in the engine manuals.

Request for Confirmation of Terminating Action

    One commenter requests that the FAA confirm if there is a 
terminating action for the repetitive clearance and alignment check in 
accordance with the engine manual. The commenter questions if 
replacement of the pressure tube in accordance with PW SB 5707 and 
JT9D-7R4-72-289 constitutes the terminating action.
    The FAA does not agree. There is no terminating action for this 
inspection. The inspections are required to make sure that there is 
sufficient tube clearance and that the TEC strut is aligned correctly. 
This inspection is an integral part of maintaining the airworthiness of 
this tube.

FAA's Determination

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Economic Analysis

    There are approximately 2,310 engines of the affected design in the 
worldwide fleet. Approximately 1,183 of these engines are installed on 
airplanes of U.S. registry. Review of purchase orders indicate that 
approximately 1,547 pressure tubes have been sold to the airlines; 
therefore this action will affect no more than 763 engines. It will 
take approximately one work hour per engine to accomplish the proposed 
actions; the average labor rate is $60 per work hour. Required parts 
will cost approximately $1,465 per engine. Based on these figures, the 
total cost impact of the proposed AD on U.S. operators is estimated to 
be no more than $1,163,575.

Regulatory Impact

    This rule does not have federalism implications, as defined in 
Executive Order 13132, because it does 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 rule.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and is

[[Page 69662]]

contained in the Rules Docket. A copy of it may be obtained from the 
Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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:

2000-23-14  Pratt & Whitney: Amendment 39-11986. 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 (BG 700) 
series turbofan engines, installed on but not limited to Boeing 747 
and 767, Airbus A300, and McDonnell Douglas DC-10 series airplanes.

    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 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 disassembly of the turbine exhaust case (TEC) 
when all hardware is stripped from the case 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 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, 770407, 770408, and 777210, Section 72-53-01, Turbine 
Exhaust Case Assembly--Inspection 01; P/N 785059, Section 72-53-05, 
Turbine Exhaust Case Assembly--Inspection/Check-01-Config-2; and P/N 
754459, Turbine Exhaust Section--Heavy Maintenance, Section 72-53-
01, Turbine Exhaust Case Assembly--Check, as follows:
    (1) Initially inspect at the next disassembly of the TEC when 
all hardware is stripped from the case after the effective date of 
this AD.
    (2) Thereafter, inspect at every disassembly of the TEC when all 
hardware is stripped from the case.

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 (ECO). 
Operators shall submit their request through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, ECO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the ECO.

Special Flight Permits

    (d) Special flight permits may be issued in accordance with 
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.

Incorporation by Reference

    (e) The replacement of the oil pressure tube shall be done in 
accordance with PW Service Bulletin No. 5707, pages 1-7, dated 
September 17, 1986, and PW Service Bulletin No. JT9D-7R4-72-289, 
pages 1-6, dated March 26, 1986. The initial and repetitive 
inspections shall be done in accordance with the specified sections 
of the appropriate PW JT9D Engine Manual:

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               P/N                      Section               Pages                         Date
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646028..........................  72-53-01...........  805-809............  March 1, 1999.
754459..........................  72-53-01...........  508................  October 15, 1999.
754459..........................  72-53-01...........  508A-508D..........  April 15, 1999.
770407..........................  72-53-01...........  805................  March 1, 1999.
770408..........................  72-53-01...........  805................  March 1, 1999.
777210..........................  72-53-01...........  805-806............  October 15, 1998.
777210..........................  72-53-01...........  807................  April 15, 1999.
777210..........................  72-53-01...........  815-818............  October 15, 1998.
785059..........................  72-53-05...........  803................  March 15, 1999.
785059..........................  72-53-05...........  807-810............  March 15, 1999.
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    This incorporation by reference was approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51. Copies may be obtained from Pratt & Whitney, 400 Main 
Street, East Hartford, CT 06108; telephone: (860) 565-6600, fax: 
(860) 565-4503. Copies may be inspected at the FAA, New England 
Region, Office of the Regional Counsel, 12 New England Executive 
Park, Burlington, MA; or at the Office of the Federal Register, 800 
North Capitol Street, NW., suite 700, Washington, DC.

Effective Date

    (f) This amendment becomes effective on January 19, 2001.

    Issued in Burlington, Massachusetts, on November 7, 2000.
Donald E. Plouffe,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 00-29212 Filed 11-17-00; 8:45 am]
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