[Federal Register Volume 59, Number 156 (Monday, August 15, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-19354]
[[Page Unknown]]
[Federal Register: August 15, 1994]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 91-ANE-51; Amendment 39-8987; AD 94-15-16]
Airworthiness Directives; Pratt & Whitney JT9D Series Turbofan
Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to Pratt & Whitney JT9D series turbofan engines, that
requires a one-time modification and overhaul of engine control system
accessories. This amendment is prompted by multiple engine surge and
power loss events caused by deterioration of internal components of
engine control system accessories. The actions specified by this AD are
intended to prevent the loss of engine compressor surge margin caused
by the deterioration of engine control system accessories, resulting in
an engine surge, and subsequent power loss or inflight engine shutdown.
DATES: Effective October 14, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of October 14, 1994.
ADDRESSES: The service information referenced in this AD may be
obtained from Pratt & Whitney, Publications Department, 400 Main
Street, East Hartford, CT 06108. This information may be examined at
the Federal Aviation Administration (FAA), New England Region, Office
of the Assistant Chief 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: Daniel Kerman, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; telephone (617)
238-7130; fax (617) 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) that is applicable to Pratt & Whitney (PW) JT9D series
turbofan engines was published in the Federal Register on January 5,
1993 (58 FR 275). That action proposed to require a one-time
modification and overhaul of engine control system accessories to
prevent loss of engine compressor surge margin caused by the
deterioration of engine control system accessories, resulting in an
engine surge, and subsequent power loss or inflight engine shutdown.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Several commenters question the need for the Federal Aviation
Administration (FAA) to issue an AD to improve the inflight engine
shutdown rate. The commenters cite section 39.1 of the Federal Aviation
Regulations (14 CFR 39.1) which requires that an AD be issued when an
unsafe condition exists in a product and is likely to exist or develop
in other products of the same design. The commenters further state that
an inflight engine shutdown on a multi-engine aircraft is not a safety
event but an operational restriction. The FAA does not concur. A
decrease in engine component reliability can pose a potentially unsafe
condition due to excessive inflight engine shutdown or surge rates.
After a review of the inflight engine shutdown and surge rates, the FAA
determined that certain populations of engines had a heightened
susceptibility to engine surge, but in many instances engine surge
events did not result in an actual inflight engine shutdown. For this
reason it is not sufficient to consider only inflight engine shutdown
rates. Other measures of overall engine reliability were also
considered, including component mean time between failure and
unscheduled removal rates. The requirements of this AD will help
preclude an incident where multiple engines on the same aircraft surge,
with or without a resultant inflight engine shutdown. The FAA has
received 12 reports of multiple engine surge events occurring during
critical phases of flight such as takeoff and climb-out; therefore, the
FAA has determined that an unsafe condition exists in a product that is
likely to exist or develop in other products of the same type design
and, accordingly, AD action is warranted.
One commenter states that the AD should be revised to require
incorporation of its provisions into an operator's existing FAA-
approved maintenance program, and that once incorporated into the
program, the AD would no longer be applicable. In addition, the
commenter suggests that the FAA Flight Standards District Offices
should administer the maintenance program. The FAA does not concur.
This AD will restore engine component reliability through incorporation
of certain design upgrades. These upgrades are necessary due to design
deficiencies of these components. This AD will not require periodic
maintenance, but only a one-time incorporation of certain service
bulletin (SB) upgrades. The FAA has, however, approved guidance titled,
``Guidance Criteria for Overhaul,'' which is incorporated as a separate
document into the latest revisions to the components' maintenance
manuals (MM). This document essentially provides for incorporation of
the SB's required by this AD, and also requires replacement of all
disposable packings and seals. The guidance provides suggested
maintenance intervals consistent with mean time between failure rates
for each component.
Several commenters request as an alternate means of compliance to
the modification required by PW SB No. 5889, that the FAA include in
this AD the tap and torque procedure described in the applicable engine
MM. The FAA does not concur. The tap and torque procedure has not
provided consistent fault-proof installation of engine main fuel pumps.
Revision 6 to PW SB No. 5889 introduces the improved QAD ring with the
necessary featural changes to alleviate the possibility of a
maintenance-induced error during the installation of an engine main
fuel pump. The FAA has incorporated Revision 6 into this AD.
One commenter states that rather than specifying ``Time Since Last
Overhaul'' the AD should read ``Time Since Limited Overhaul.'' The FAA
does not concur. The intervals specified in this AD are based on time
since a complete overhaul accomplished in accordance with the
components' MM. Previous revisions to the components' MM's did not
include a defined procedure for limited overhaul. Therefore, there is
no standard by which the FAA can evaluate whether the limited overhaul
procedures will accomplish the necessary design upgrades, and the
commenter does not include supporting data. The latest revisions to the
components' MM's, in the section titled ``Guidance Criteria for
Overhaul,'' defines what is required to perform a limited overhaul on
these components. If an operator satisfies these minimum criteria and
has data to demonstrate low inflight engine shutdown and surge rates,
the operator may apply for an alternate means of compliance with this
AD.
One commenter states that Hamilton Standard (HS) SB No. JFC68 73-19
should be referred to as a ``General'' SB in order to avoid confusion.
The FAA concurs and the final rule has been changed accordingly.
One commenter states that HS SB No. JFC68-3 73-150 requires
installation of components that are then replaced during accomplishment
of HS SB No. JFC68-3 73-151, and that HS SB No. JFC68-4 73-50 requires
installation of components that are then replaced during accomplishment
of HS SB No. JFC68-4 73-51. The commenter questions if it is acceptable
to install the most recent parts. The FAA concurs. The reliability
aspects of the requirements of HS SB No. JFC68-3 73-150 and HS SB No.
JFC68-3 73-151, and HS SB No. JFC68-4 73-50 and HS SB No. JFC68-4 73-
51, are similar. Accomplishment of HS SB No. JFC68-3 73-151 and HS SB
No. JFC68-4 73-51 in lieu of HS SB No. JFC68-3 73-150 and HS SB No.
JFC68-4 73-50, respectively, constitute an acceptable alternate means
of compliance for this AD.
One commenter states that HS MM 73-21-01, Revision 19, is dated
January 15, 1992, not June 15, 1991. The FAA concurs and has changed
the AD accordingly.
One commenter states that HS SB No. 75-49 requires components to be
reidentified to L47, not L30. The FAA concurs and has changed the AD
accordingly.
One commenter states that HS SB No. 75-27 has not been revised. The
FAA concurs and has changed the AD accordingly.
Several commenters address that HS Engine Vane Control (EVC)3-5 is
not applicable to the PW Model JT9D-7Q engine. The FAA concurs and has
changed the AD accordingly.
Several commenters state that TRW (formerly Argo-Tech) SB 73-43
does not include the PW Models JT9D-20 or -20J engines and question if
compliance will be required for these models. The FAA concurs. PW has
released SB No. 6127, dated September 10, 1993, that includes the PW
JT9D-20 and -20J engine models. This SB in turn makes reference to
Argo-Tech SB No. 73-43, which calls for modification of the PW Models
JT9D-20 and -20J fuel pump to accommodate the new QAD ring. The FAA has
changed the AD accordingly to include this SB.
One commenter states that soft-time requirements would be
preferable to hard time requirements for one-time overhaul and
modification of engine accessories. The FAA does not concur. Most
significantly, many operators have decided to postpone accessory
upgrades recommended by PW. The FAA's analysis indicates that
postponing these upgrades has a cumulative effect which has resulted in
a degradation of component reliability and loss of engine surge margin.
The FAA conducted an industry-wide survey and determined that there is
a direct correlation between accessory build standard and engine surge
rate. There is also a direct correlation between time between accessory
overhaul and loss of engine surge margin due to the degradation of the
accessories. The one-time overhaul and modifications required by this
AD have been established based on the FAA's review of inflight engine
shutdown and surge rates. The FAA recommends that following
accomplishment of the one-time overhaul and modifications required by
this AD, all operators establish a soft-time overhaul interval for
maintenance of engine accessories in accordance with the ``Guidance
Criteria for Overhaul'' incorporated into the components' MM's.
One commenter states that the AD does not clearly state that the
overhaul requirement for the accessories is a one-time overhaul. The
FAA concurs and has changed the AD accordingly to emphasize that this
overhaul is a one-time requirement only.
One commenter questions why the threshold for overhaul is 12,000
hours time in service (TIS) for the EVC and 10,000 hours for the Engine
Vane and Bleed Control (EVBC). The commenter states that the EVBC is
more reliable than the EVC. The FAA does not concur. The fleet survey
provided data on mean time failure rates from which the overhaul
intervals specified in this AD were derived. Based on this review, the
FAA has determined that maximum time between overhauls should be 12,000
hours TIS for EVC's and 10,000 hours TIS for EVBC's. If an operator can
provide enhanced reliability data through improved maintenance
procedures, the FAA may consider this data as an acceptable alternate
means of compliance for this AD.
One commenter states that the AD does not account for operators'
responsiveness to vendor recommended modifications and that the AD
requires immediate incorporation of SB's assigned a low to medium
priority by the Original Equipment Manufacturer. The FAA does not
concur. The FAA conducted a fleet survey which showed that most
operators lacked adequate accessory build standards and that this
inadequacy had a direct effect on engine surge and inflight shutdown
rates. Furthermore, those operators that have incorporated the
modifications required by this AD, satisfy the intent of this AD, and
no further action is required. Regarding the SB's priority, the FAA has
determined that all the required SB's have a significant effect on
engine surge margin regardless of SB category.
One commenter states that the AD is contradictory about previous
accomplishment. The commenter references paragraphs (a)(3), (a)(4),
(b)(3), (b)(4), (c)(3), (c)(4) of the AD. The FAA does not concur.
These paragraphs state that previous accomplishment for overhaul is
based on Time Since Overhaul, and extend credit to those operators who
have already accomplished overhaul provided they are within the
prescribed intervals specified by the AD. As to the paragraphs
requiring modifications, if the operator has implemented all the SB's
referenced in the AD, then the operator has accomplished previously the
modification requirements of this AD.
One commenter states that the AD will require all their components
to be overhauled and modified by the calendar end date of January 31,
1995, based on the operator's maintenance program, which will require
overhaul of all components disassembled to the extent required for
these modifications. The FAA does not concur. An individual operator's
FAA-approved maintenance program may dictate that the components must
be overhauled by a certain date, but for other operators there may be
instances where certain components may remain in service past the
calendar-end date. In the NPRM, paragraphs (a)(3), (b)(3), (c)(3), and
(d)(3) stated that certain components must be overhauled prior to a
certain TIS, or January 31, 1995, whichever occurs later. Since
publication of that NPRM, the FAA has determined to extend the
compliance end date to July 31, 1995, due to the time required to
adequately address all comments and publish the final rule.
One commenter states that the AD would require, based on current
aircraft utilization, the majority of Fuel Control Units to be modified
within 250 days after the effective date of this AD. The FAA concurs.
The FAA has determined that the drawdown intervals defined in this AD
constitute an acceptable minimum standard of airworthiness for the PW
JT9D fuel control.
One commenter states that monitoring of engine condition is not
taken into account as a compliance option in the AD. The FAA concurs.
However, this data could be used as substantiation for an alternate
means of compliance.
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.
The FAA estimates that approximately 300 engines of the affected
design installed on aircraft of U.S. registry will be affected by this
AD, that it will take approximately 30 work hours per engine to
accomplish the required actions, and that the average labor rate is $55
per work hour. Required parts will cost approximately $13,100 per
engine. Based on these figures, the total cost impact of the AD on U.S.
operators is estimated to be $4,425,000.
The regulations adopted herein will 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 final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory activity'' 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 it is 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. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
94-15-16 Pratt & Whitney: Amendment 39-8987. Docket 91-ANE-51.
Applicability: Pratt & Whitney (PW) Model JT9D-3A, -7, -7A, -
7AH, -7H, -7F, -7J, -20, -20J, -59A, -70A, and -7Q turbofan engines
installed on but not limited to Boeing 747 series, McDonnell Douglas
DC-10 series, and Airbus A300 series aircraft.
Compliance: Required as indicated, unless accomplished
previously.
To prevent the loss of engine compressor surge margin caused by
the deterioration of engine control system accessories, resulting in
an engine surge, and subsequent power loss or inflight engine
shutdown, accomplish the following:
(a) Perform a one-time overhaul and modification of the main
fuel controls as follows:
(1) For main fuel controls with either 12,000 hours or more time
since overhaul (TSO) on the effective date of this AD or with an
undocumented TSO, or for those main fuel controls that have never
been overhauled and have either 12,000 hours or more time since new
(TSN) on the effective date of this AD or an undocumented TSN,
overhaul in accordance with the applicable Hamilton Standard (HS)
Maintenance Manual (MM) listed in Table 1 of this AD, and modify in
accordance with the applicable HS Service Bulletins (SB) listed in
Table 2 of this AD, at the earliest of: the next shop visit; 3,000
hours time in service (TIS) after the effective date of this AD; or
July 31, 1995.
(2) For main fuel controls with more than 10,000 hours but less
than 12,000 hours TSO, or TSN if never overhauled, on the effective
date of this AD, overhaul in accordance with the applicable HS MM
listed in Table 1 of this AD, and modify in accordance with the
applicable HS SB's listed in Table 2 of this AD, not later than
3,000 hours TIS after the effective date of this AD, or by July 31,
1995, whichever occurs first.
(3) For main fuel controls with 10,000 hours or less TSO, or TSN
if never overhauled, on the effective date of this AD, overhaul in
accordance with the applicable HS MM listed in Table 1 of this AD,
not later than 12,000 hours TSO or TSN, or by July 31, 1995,
whichever occurs later.
(4) For main fuel controls with 10,000 hours or less TSO, or TSN
if never overhauled, on the effective date of this AD, modify in
accordance with the applicable HS SB's listed in Table 2 of this AD,
not later than 12,000 hours TSO or TSN, or by July 31, 1995,
whichever occurs first.
Table 1.--Engine Accessory Overhaul Reference List
----------------------------------------------------------------------------------------------------------------
Accessory description Hamilton standard maint. manual No. Temporary revision No.
----------------------------------------------------------------------------------------------------------------
Main fuel controls:
JFC68-3...................... 73-21-01, Revision 19, dated January 15, 73-54, dated June 15, 1992.
1992.
JFC68-4...................... 73-21-02, Revision 10, dated January 15, 73-31, dated June 15, 1992.
1992.
JFC68-6...................... 73-21-03, Revision 10, dated September 15, N/A.
1992.
Engine vane controls:
EVC3-2 and EVC3-4............ 75-31-01, Revision 20, dated July 1, 1992.. 75-26, dated July 15, 1993.
EVC3-5....................... 75-32-01, Revision 9, dated June 15, 1986.. 75-5, dated July 1, 1992.
Engine vane and bleed controls:
GTA9-1 and GTA9-2............ 75-34-01, Revision 11, dated August 15, N/A.
1992.
----------------------------------------------------------------------------------------------------------------
Table 2.--Hamilton Standard Main Fuel Control Unit (FCU) Service
Bulletin Incorporation List
------------------------------------------------------------------------
FCU model JFC68-3, JT9D- FCU model JFC68-4, JT9D- FCU model JFC68-6,
3A, -7 series engines 20, -20J series engines JT9D-59A, -70A, -7Q
series engines
------------------------------------------------------------------------
73-150 (L160), Revision 73-50 (L94), Revision 73-23 (L30), Revision
1, dated 8-15-91. 2, dated 12-13-93. 1, dated 8-15-91.
73-139 (L152), 73-42 (L87), Original, N/A.
Original, dated 2-27- dated 2-27-76.
76.
73-129 (L143), Revision 73-36 (L81), Revision 73-3 (L14), Original,
3, dated 7-1-77. 3, dated 7-1-77. dated 1-7-77.
73-128 (L142), Revision 73-35 (L80), Revision N/A.
1, dated 8-29-75. 1, dated 8-29-75.
73-127 (L141), Revision 73-33 (L79), Revision N/A.
2, dated 10-31-78. 2, dated 10-31-78.
73-122 (L137), Revision 73-29 (L75), Revision N/A.
1, dated 9-27-77. 1, dated 9-27-77.
73-121 (L136), 73-28 (L74), Original, N/A.
Original, dated 5-29- dated 5-29-74.
74.
73-117 (L133), Revision 73-24 (L71), Revision N/A.
3, dated 10-15-74. 2, dated 10-15-74.
73-111 (L128), Revision 73-21 (L69), Revision N/A.
1, dated 10-27-76. 1, dated 10-27-76.
N/A.................... N/A.................... 73-27 (L33), Revision
1, dated 9-27-82.
73-19, General, 73-19, General, 73-19, General,
Revision 1, dated 9-20- Revision 1, dated 9-20- Revision 1, dated 9-
86. 86. 20-86.
------------------------------------------------------------------------
(b) Perform a one-time overhaul and modification of engine vane
controls as follows:
(1) For engine vane controls with either 12,000 hours or more
TSO on the effective date of this AD or with an undocumented TSO, or
for those engine vane controls that have never been overhauled and
have either 12,000 hours or more TSN on the effective date of this
AD or an undocumented TSN, overhaul in accordance with the
applicable HS MM listed in Table 1 of this AD, and modify in
accordance with the applicable HS SB's listed in Table 3 of this AD,
at the earliest of: the next shop visit; 3,000 hours time in service
(TIS) after the effective date of this AD; or July 31, 1995.
(2) For engine vane controls with more than 10,000 hours but
less than 12,000 hours TSO, or TSN if never overhauled, on the
effective date of this AD, overhaul in accordance with the
applicable HS MM listed in Table 1 of this AD, and modify in
accordance with the applicable HS SB's listed in Table 3 of this AD,
not later than 3,000 hours TIS after the effective date of this AD,
or by July 31, 1995, whichever occurs first.
(3) For engine vane controls with 10,000 hours or less TSO, or
TSN if never overhauled, on the effective date of this AD, overhaul
in accordance with the applicable HS MM listed in Table 1 of this
AD, not later than 12,000 hours TSO or TSN, or by July 31, 1995,
whichever occurs later.
(4) For engine vane controls with 10,000 hours or less TSO, or
TSN if never overhauled, on the effective date of this AD, modify in
accordance with the applicable HS SB's listed in Table 3 of this AD
not later than 12,000 hours TSO or TSN, or by July 31, 1995,
whichever occurs first.
Table 3.--Hamilton Standard Engine Vane Control (EVC) Recommended
Service Bulletin Incorporation List
------------------------------------------------------------------------
EVC3-2 model JT9D-3A, - EVC3-4 model JT9D-20, - EVC3-5 model JT9D-59A,
7 series engines 20J series engines -70A series engines
------------------------------------------------------------------------
75-48 (L46), Revision 75-27 (L33), Revision 75-9 (L10), Revision
1, dated 8-6-91. 1, dated 8-19-91. 1, dated 8-21-91.
75-45 (L43), Revision 75-24 (L30), Revision 75-6 (L7), Revision 1,
1, dated 8-16-91. 1, dated 8-19-91. dated 8-20-91.
75-43 (L42), Revision 75-23 (L29), Original, 75-5, Original, dated
2, dated 4-25-91. dated 3-31-88. 3-31-88.
75-41 (L41), Revision 75-22 (L28), Revision 75-4 (L5), Revision 2,
3, dated 8-16-91. 1, dated 8-19-91. dated 8-20-91.
75-42, Revision 1, N/A.................... N/A.
dated 8-16-91.
75-37 (L40), Revision 75-19 (L27), Revision 75-2 (L4), Revision 1,
3, dated 8-16-91. 3, dated 8-19-91. dated 11-8-79.
75-36, Revision 1, 75-20, Original dated 9- N/A.
dated 9-1-78. 1-78.
75-31 (L35), Original, 75-14 (L22), Original, N/A.
dated 5-23-75. dated 5-23-75.
75-28 (L33), Original, 75-11 (L20), Original, N/A.
dated 1-3-75. dated 1-3-75.
75-27 (L32), Original, 75-10 (L19), Original, N/A.
dated 9-10-74. dated 9-10-74.
75-49 (L47), Original, 75-28 (L34), Original, N/A.
dated 5-13-91. dated 5-13-91.
------------------------------------------------------------------------
(c) Perform a one-time overhaul and modification of engine vane
and bleed controls as follows:
(1) For engine vane and bleed controls with either 10,000 hours
or more TSO on the effective date of this AD or with an undocumented
TSO, or for those engine vane and bleed controls that have never
been overhauled and have either 10,000 hours or more TSN on the
effective date of this AD or an undocumented TSN, overhaul in
accordance with the applicable HS MM listed in Table 1 of this AD,
and modify in accordance with the applicable HS SB's listed in Table
4 of this AD, at the earliest of: the next shop visit; 3,000 hours
TIS after the effective date of this AD; or July 31, 1995.
(2) For engine vane and bleed controls with more than 8,000
hours but less than 10,000 hours TSO, or TSN if never overhauled, on
the effective date of this AD, overhaul in accordance with the
applicable HS MM listed in Table 1 of this AD, and modify in
accordance with the applicable HS SB's listed in Table 4 of this AD,
not later than 3,000 hours TIS after the effective date of this AD,
or by July 31, 1995, whichever occurs first.
(3) For engine vane and bleed controls with 8,000 hours or less
TSO, or TSN if never overhauled, on the effective date of this AD,
overhaul in accordance with the applicable HS MM listed in Table 1
of this AD, not later than 10,000 hours TSO or TSN, or by July 31,
1995, whichever occurs later.
(4) For engine vane and bleed controls with 8,000 hours or less
TSO, or TSN if never overhauled, on the effective date of this AD,
modify in accordance with the applicable HS SB's listed in Table 4
of this AD, not later than 10,000 hours TSO or TSN, or by July 31,
1995, whichever occurs first.
Table 4.--Hamilton Standard Engine Vane Bleed Control (EVBC) (GTA9)
Required Service Bulletin Incorporation List
JT9D-59A, -70A, -7Q, Series Engines
------------------------------------------------------------------------
Service bulletin Revision Date
------------------------------------------------------------------------
GTA9-75-26 (L21).............................. 1............ 8-21-91
GTA9-75-19 (L14).............................. 1............ 8-21-91
GTA9-75-17 (L13).............................. Original..... 3-31-88
GTA9-75-16 (L12).............................. Original..... 3-20-88
GTA9-75-9 (L8)................................ 3............ 8-15-92
------------------------------------------------------------------------
(d) Perform a one-time overhaul and modification of main fuel
gear pumps as follows:
(1) For main fuel gear pumps with either 8,000 hours or more TSO
on the effective date of this AD or with an undocumented TSO, or for
those main fuel gear pumps that have never been overhauled and have
either 8,000 hours or more TSN on the effective date of this AD or
an undocumented TSN, overhaul in accordance with either Argo-Tech
(AT) Overhaul Manual (OM) No. 73-11-01 or No. 73-11-02, as
applicable, and modify in accordance with the applicable TRW, AT,
and Pratt & Whitney (PW) SB's listed in Table 5 of this AD, at the
earliest of: the next shop visit; 3,000 hours TIS after the
effective date of this AD; or July 31, 1995.
(2) For main fuel gear pumps with more than 6,000 hours but less
than 8,000 hours TSO, or TSN if never overhauled, on the effective
date of this AD, overhaul in accordance with either AT OM No. 73-11-
01 or No. 73-11-02, as applicable, and modify in accordance with the
applicable TRW, AT, and PW SB's listed in Table 5 of this AD, not
later than 3,000 hours TIS after the effective date of this AD, or
by July 31, 1995, whichever occurs first.
(3) For main fuel gear pumps with 6,000 hours or less TSO, or
TSN if never overhauled, on the effective date of this AD, overhaul
in accordance with either AT OM No. 73-11-01 or No. 73-11-02, as
applicable, not later than 8,000 hours TSO or TSN, or by July 31,
1995, whichever occurs later.
(4) For main fuel gear pumps with 6,000 hours or less TSO, or
TSN if never overhauled, on the effective date of this AD, modify in
accordance with the applicable TRW, AT and PW SB's listed in Table 5
of this AD, not later than 8,000 hours TSO or TSN, or by July 31,
1995, whichever occurs first.
Table 5.--TRW, AT, and PW Main Fuel Gear Pump Required Service Bulletin
Incorporation List
------------------------------------------------------------------------
JT9D-3A, -7, -20, -20J series
engines JT9D-59A, -70A, -7Q series engines
------------------------------------------------------------------------
TRW 73-28 (-26), Revision 2, dated N/A.
4-15-77.
TRW 73-29 (-27), Revision 1, dated TRW 73-5 (-9), Original, dated 4-30-
9-1-80. 81.
TRW 73-31 (-29), Original, dated 9- N/A.
1-79.
TRW 73-32 (-30), Revision 3, dated N/A.
4-1-85.
AT 73-36 (-32), Revision 1, dated N/A.
10-1-88.
AT 73-43, Original, dated 12-15-89. N/A.
N/A................................ TRW 73-8 (-12) Original, dated 9-1-
82.
PW 5889, Revision 6, dated 12-20-93 N/A.
PW 6127, Original, dated 9-10-93... N/A.
------------------------------------------------------------------------
(e) For the purpose of this AD, a shop visit is defined as an
engine removal where engine maintenance entails separation of pairs
of mating engine flanges or the removal of a disk, hub, or spool.
(f) 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. The
request should be forwarded through an FAA Principal Maintenance
Inspector, who may add comments and then send it to the Manager,
Engine Certification Office.
Note: Information concerning the existence of approved
alternative methods of compliance with this airworthiness directive,
if any, may be obtained from the Engine Certification Office.
(g) 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 aircraft to a location where
the requirements of this AD can be accomplished.
(h) The overhauls and modifications shall be done in accordance
with the following service bulletins:
----------------------------------------------------------------------------------------------------------------
SB No. Pages Revision Date
----------------------------------------------------------------------------------------------------------------
TRW SB No. 73-28........................ 1......................... 2......................... 4-15-77
2......................... 1......................... 1-15-77
3......................... 2......................... 4-15-77
4......................... 1......................... 1-15-77
4A........................ 2......................... 4-15-77
5-7....................... 1......................... 1-15-77
8......................... 2......................... 4-15-77
9-10...................... 1......................... 1-15-77
Total Pages: 10
TRW SB No. 73-29........................ 1......................... 1......................... 9-1-80
2......................... Original.................. 3-1-79
3......................... 1......................... 9-1-80
4......................... Original.................. 3-1-79
Total Pages: 4
TRW SB No. 73-31........................ 1-3....................... Original.................. 9-1-79
Total Pages: 3
TRW SB No. 73-32........................ 1-3....................... 3......................... 4-1-85
4......................... 1......................... 6-15-81
Total Pages: 4
Argo-Tech SB No. 73-36.................. 1-3....................... 1......................... 10-1-88
Total Pages: 3
Argo-Tech SB No. 73-43.................. 1......................... Original.................. 12-15-89
Total Pages: 4
TRW SB No. 73-8......................... 1-4....................... Original.................. 9-1-82
Total Pages: 4
TRW SB No. 73-5......................... 1-3....................... Original.................. 4-30-81
Total Pages: 3
PW SB No. 5889.......................... 1......................... 6......................... 12-20-93
2......................... 5......................... 9-21-92
3-5....................... Original.................. 12-21-89
6......................... 4......................... 5-7-92
7-8....................... Original.................. 12-21-89
9-11...................... 3......................... 10-4-91
12........................ 1......................... 1-24-90
13........................ 4......................... 5-7-92
14-18..................... Original.................. 12-21-89
19........................ 6......................... 12-20-93
20........................ 4......................... 5-7-92
Total Pages: 20
PW SB No. 6127.......................... 1-14...................... Original.................. 9-10-93
Total Pages: 14
HS SB No. GTA9-75-26.................... 1-3....................... 1......................... 8-21-91
4-6....................... Original.................. 5-9-90
Total Pages: 6
HS SB No. GTA9-75-19.................... 1-4....................... 1......................... 8-21-91
Total Pages: 4
HS SB No. GTA9-75-17.................... 1-3....................... Original.................. 3-31-88
Total Pages: 3
HS SB No. GTA9-75-16.................... 1-3....................... Original.................. 3-20-88
Total Pages: 3
HS SB No. GTA9-75-9..................... 1-2....................... 3......................... 8-15-92
3-7....................... 2......................... 8-21-91
Total Pages: 7
HS SB No. 75-9.......................... 1-2....................... 1......................... 8-20-91
2A/2B..................... 1......................... 8-20-91
3-6....................... Original.................. 5-9-90
Total Pages: 7
HS SB No. 75-6.......................... 1-3....................... 1......................... 8-20-91
Total Pages: 3
HS SB No. 75-5.......................... 1-3....................... Original.................. 3-31-88
Total Pages: 3
HS SB No. 75-4.......................... 1-3....................... 2......................... 8-20-91
4-7....................... 1......................... 10-15-84
Total Pages: 7
HS SB No. 75-2.......................... 1-7....................... 1......................... 11-8-79
Total Pages: 7
HS SB No. 75-28......................... 1-4....................... Original.................. 5-13-91
Total Pages: 4
HS SB No. 75-27......................... 1-6....................... Original.................. 8-19-91
Total Pages: 5
HS SB No. 75-24......................... 1-3....................... 1......................... 8-19-91
Total Pages: 3
HS SB No. 75-23......................... 1-3....................... Original.................. 3-31-88
Total Pages: 3
HS SB No. 75-22......................... 1-2....................... 1......................... 8-19-91
2A/2B..................... 1......................... 8-19-91
3-6....................... Original.................. 4-30-84
Total Pages: 6
HS SB No. 75-19......................... 1-2....................... 3......................... 8-19-91
2A/2B..................... 3......................... 8-19-91
3-7....................... 2......................... 11-8-79
Total Pages: 7
HS SB No. 75-20......................... 1-3....................... Original.................. 9-1-78
Total Pages: 3
HS SB No. 75-14......................... 1-4....................... Original.................. 5-23-75
Total Pages: 4
HS SB No. 75-11......................... 1-3....................... Original.................. 1-3-75
Total Pages: 3
HS SB No. 75-10......................... 1-5....................... Original.................. 9-10-74
Total Pages: 5
HS SB No. 75-49......................... 1-4....................... Original.................. 5-13-91
Total Pages: 4
HS SB No. 75-48......................... 1-2....................... 1......................... 8-16-91
3-6....................... Original.................. 5-9-90
Total Pages: 6
HS SB No. 75-45......................... 1-4....................... 1......................... 8-16-91
Total Pages: 4
HS SB No. 75-43......................... 1-4....................... 2......................... 4-25-91
Total Pages: 4
HS SB No. 75-42......................... 1-2....................... 1......................... 8-16-91
Total Pages: 2
HS SB No. 75-41......................... 1-3....................... 3......................... 8-16-91
4-7....................... 2......................... 12-20-90
Total Pages: 7
HS SB No. 75-37......................... 1-2....................... 3......................... 8-16-91
2A/2B..................... 3......................... 8-16-91
3-7....................... 2......................... 12-12-79
Total Pages: 8
HS SB No. 75-36......................... 1-3....................... Revision 1................ 9-1-78
Total Pages: 3
HS SB No. 75-31......................... 1-4....................... Original.................. 5-23-75
Total Pages: 4
HS SB No. 75-28......................... 1-3....................... Original.................. 1-3-75
Total Pages: 3
HS SB No. 75-27......................... 1-5....................... Original.................. 9-10-74
Total Pages: 6
HS General SB No. 73-19................. 1-3....................... 1......................... 9-20-86
4......................... Original.................. 12-15-84
5-6....................... 1......................... 9-20-86
Total Pages: 6
HS SB No. 73-27......................... 1-2....................... 1......................... 9-27-82
3-4....................... Original.................. 2-10-82
5......................... 1......................... 9-27-82
Total Pages: 5
HS SB No. 73-23......................... 1-2....................... 1......................... 8-15-91
2A/2B..................... 1......................... 8-15-91
3-5....................... Original.................. 4-30-81
Total Pages: 5
HS SB No. 73-3.......................... 1-5....................... Original.................. 1-7-77
Total Pages: 5
HS SB No. 73-50......................... 1-2....................... 2......................... 12-13-92
2A/2B..................... 1......................... 8-15-91
3......................... Original.................. 4-30-81
4-5....................... 2......................... 12-13-92
Total Pages: 5
HS SB No. 73-42......................... 1-3....................... Original.................. 2-27-76
Total Pages: 3
HS SB No. 73-36......................... 1......................... 3......................... 7-1-77
2......................... 1......................... 11-5-76
3......................... 3......................... 7-1-77
4......................... 2......................... 4-20-77
5......................... 3......................... 7-1-77
Total Pages: 5
HS SB No. 73-35......................... 1-2....................... 1......................... 8-29-75
3-4....................... Original.................. 4-22-75
5-6....................... 1......................... 8-29-75
7......................... Original.................. 4-22-75
Total Pages: 7
HS SB No. 73-33......................... 1......................... 2......................... 10-31-78
2......................... 1......................... 3-5-76
3-4....................... 2......................... 10-31-78
5......................... 1......................... 3-5-76
Total Pages: 5
HS SB No. 73-29......................... 1-3....................... 1......................... 9-27-77
4-5....................... Original.................. 2-7-75
6-7....................... 1......................... 9-27-77
Total Pages: 7
HS SB No. 73-28......................... 1-5....................... Original.................. 5-29-74
Total Pages: 5
HS SB No. 73-24......................... 1-2....................... 2......................... 10-15-74
3-5....................... Original.................. 11-16-73
Total Pages: 5
HS SB No. 73-21......................... 1-8....................... 1......................... 10-27-76
Total Pages: 8
HS SB No. 73-150........................ 1-2B...................... 1......................... 8-15-91
3-5....................... Original.................. 4-30-81
Total Pages: 5
HS SB No. 73-139........................ 1-3....................... Original.................. 2-27-76
Total Pages: 3
HS SB No. 73-129........................ 1......................... 3......................... 7-1-77
2......................... Original.................. 2-21-75
3......................... 3......................... 7-1-77
4......................... 2......................... 4-20-77
5......................... 3......................... 7-1-77
Total Pages: 5
HS SB No. 73-128........................ 1-3....................... 1......................... 8-29-75
4......................... Original.................. 4-22-75
5......................... 1......................... 8-29-75
6-7....................... Original.................. 4-22-75
Total Pages: 7
HS SB No. 73-127........................ 1......................... 2......................... 10-31-78
2......................... Original.................. 3-12-75
3-6....................... 2......................... 10-31-78
Total Pages: 6
HS SB No. 73-122........................ 1......................... 1......................... 9-27-77
2......................... Original.................. 2-7-75
3......................... 1......................... 9-27-77
4-5....................... Original.................. 2-7-75
6-7....................... 1......................... 9-27-77
Total Pages: 7
HS SB No. 73-121........................ 1-5....................... Original.................. 5-29-74
Total Pages: 5
HS SB No. 73-117........................ 1-2....................... 3......................... 10-15-74
3-5....................... Original.................. 11-16-73
Total Pages: 5
HS SB No. 73-111........................ 1-8....................... 1......................... 10-27-76
Total Pages: 8
----------------------------------------------------------------------------------------------------------------
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, Technical
Publications Department, M/S 132-30, 400 Main Street, East Hartford,
CT 06108. Copies may be inspected at the FAA, New England Region,
Office of the Assistant Chief 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.
(i) This amendment becomes effective on October 14, 1994.
Issued in Burlington, Massachusetts, on July 28, 1994.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 94-19354 Filed 8-12-94; 8:45 am]
BILLING CODE 4910-13-P