[Federal Register Volume 60, Number 98 (Monday, May 22, 1995)]
[Rules and Regulations]
[Pages 27020-27023]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-12328]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-ANE-21; Amendment 39-9227; AD 95-10-10]
Airworthiness Directives; Pratt & Whitney JT8D Series Turbofan
Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to certain Pratt & Whitney (PW) JT8D series turbofan
engines, that currently requires initial and repetitive inspections of
certain front compressor fan hubs and shotpeening of the forward and
aft rim to web radius. This amendment requires a reduction in the
initial inspection interval for front compressor fan hubs installed in
all positions of all applicable aircraft, establish a compliance end-
date, and clarify the wording of the compliance requirements. This
amendment is [[Page 27021]] prompted by a report of a front compressor
fan hub fracture installed in a Boeing 737 aircraft that resulted in
the release of fan blades and portions of the hub outer rim. The
actions specified by this AD are intended to prevent fracture of the
front compressor fan hub, which can result in an uncontained engine
failure and damage to the aircraft.
DATES: Effective July 21, 1995.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of July 21, 1995.
ADDRESSES: The service information referenced in this AD may be
obtained from Pratt & Whitney, Technical Publications Department, M/S
132-30, 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: Mark A. Rumizen, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA, 01803-5299; telephone (617)
238-7137 , fax (617) 238-7199.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) by superseding AD 93-14-14,
Amendment 39-8638 (58 FR 39644, July 26, 1993) which is applicable to
PW JT8D series turbofan engines, was published in the Federal Register
on November 21, 1994 (59 FR 59973). That action proposed to reduce the
initial inspection interval to require front compressor fan hubs
installed in all positions of all applicable aircraft be inspected at
the next shop visit, and to establish a compliance end date of December
31, 1999, or 6000 total part cycles (TPC) after the effective date of
this AD for the initial inspection. That action also proposed to
clarify the wording of paragraph (b)(4) to emphasize that the
repetitive inspection is required at the next opportunity when the
front compressor fan hub is accessible at the detail level in the shop
only after accumulating 2500 additional cycles in service (CIS) since
the last inspection. The actions would be required to be accomplished
in accordance with Pratt & Whitney (PW) Alert Service Bulletin (ASB)
No. A6104, Revision 3, dated June 16, 1994.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter states that the reporting requirements of the AD be
removed. The FAA does not concur. This corrective action program was
based on a risk analysis that assumed a frequency of inspection
relative to fleet usage. The reporting requirements of the AD allow
this frequency of inspections to be monitored to ensure it is
consistent with the assumptions, thereby confirming that the corrective
action program is appropriate for maintaining the forecasted risk
level.
One commenter supports the amendment as proposed.
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 as proposed.
There are approximately 2165 engines of the affected design in the
worldwide fleet. The FAA estimates that 1475 engines installed on
aircraft of U.S. registry and 690 domestic uninstalled engines will be
affected by this AD, that it will take approximately 12 work hours per
engine to accomplish the required actions, and that the average labor
rate is $55 per work hour. Based on these figures, the total cost
impact of the AD on U.S. operators is estimated to be $1,428,900.
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 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 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 removing Amendment 39-8638 (58 FR
39644, July 26, 1993) and by adding a new airworthiness directive,
Amendment 39-9227, to read as follows:
95-10-10 Pratt & Whitney: Amendment 39-9227. Docket 94-ANE-21.
Supersedes AD 93-14-14, Amendment 39-8638.
Applicability: Pratt & Whitney (PW) Model JT8D-9, -9A, -11, -15,
-15A, -17, -17A, -17R, and -17AR turbofan engines.
Note: 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 use the
authority provided in paragraph (h) to request approval from the
Federal Aviation Administration (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 engine from the
applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent fracture of the front compressor fan hub, which can
result in an uncontained engine failure and damage to the aircraft,
accomplish the following:
(a) For front compressor fan hubs installed in engines in the
No. 2 position on Boeing 727 aircraft on or after the effective date
of this AD, inspect and shotpeen the front compressor fan hub in
accordance with Appendix A, Appendix B, and Attachment 1 (NDIP-764)
of PW Alert Service Bulletin (ASB) No. A6104, Revision 3, dated June
16, 1994, as follows: [[Page 27022]]
(1) Initially inspect the front compressor fan hub as follows:
------------------------------------------------------------------------
Total part cycles (TPC)
on the effective date of Initial inspection interval
this AD
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Over 18,001 TPC.......... Inspect at the next shop visit, or within 300
cycles in service (CIS) after the effective
date of this AD, whichever occurs first.
16,501 to 18,000 TPC..... Inspect at the next shop visit, or within 500
CIS after the effective date of this AD,
whichever occurs first.
15,001 to 16,500 TPC..... Inspect at the next shop visit, or within 750
CIS after the effective date of this AD,
whichever occurs first.
13,501 to 15,000 TPC..... Inspect at the next shop visit, or within
1,000 CIS after the effective date of this
AD, whichever occurs first.
10,501 to 13,500 TPC..... Inspect at the next shop visit, or within
1,500 CIS after the effective date of this
AD, whichever occurs first.
Less than 10,501 TPC..... Inspect at the next shop visit but not to
exceed 12,000 TPC, or by the compliance end-
date, whichever occurs first.
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(2) Engines removed from the No. 2 position on Boeing 727
aircraft and reinstalled in aircraft or positions other than the No.
2 position on Boeing 727 aircraft after the effective date of this
AD must adhere to the initial inspection interval specified in
paragraph (a)(1) of this AD. Inspect and shotpeen front compressor
fan hubs on these repositioned engines in accordance with paragraph
(a)(1) of this AD.
(3) Remove front compressor fan hubs from service if cracks are
found during the inspection process and replace with a serviceable
hub.
(4) Shotpeen the front compressor fan hubs that pass the
inspections required by paragraph (a)(1) of this AD, in accordance
with Appendix B of PW ASB No. A6104, Revision 3, dated June 16,
1994, prior to returning the hub to service.
(5) Thereafter, inspect, shotpeen, and remove from service, if
necessary, front compressor fan hubs that are reinstalled in the No.
2 position of Boeing 727 aircraft, in accordance with Appendix A,
Appendix B, and Attachment 1 (NDIP-764), as applicable, of PW ASB
No. A6104, Revision 3, dated June 16, 1994, as follows:
(i) For hubs that were last inspected and shotpeened with
greater than 12,000 TPC upon inspection, inspect and shotpeen at the
first shop visit after 2,500 CIS since last inspection, but prior to
the accumulation of 8,000 CIS since last inspection.
(ii) For hubs that were last inspected and shotpeened with less
than or equal to 12,000 TPC upon inspection, inspect and shotpeen at
the first shop visit after 2,500 CIS since last inspection, or prior
to accumulating 12,000 TPC, whichever occurs later, but not to
exceed 8,000 CIS since last inspection.
(6) Engines removed from the No. 2 position on Boeing 727
aircraft and reinstalled in aircraft or positions other than the No.
2 position on Boeing 727 aircraft prior to reaching the repetitive
inspection interval specified in paragraph (a)(5) of this AD must be
inspected as follows:
(i) For the next inspection, inspect in accordance with
paragraph (a)(5) of this AD; and
(ii) thereafter, inspect and shotpeen in accordance with
paragraph (b)(4) of this AD.
(b) For front compressor fan hubs installed in engines that are
installed in aircraft or positions other than the No. 2 position on
Boeing 727 aircraft on or after the effective date of this AD,
inspect and shotpeen the front compressor fan hubs in accordance
with Appendix A, Appendix B, and Attachment 1 (NDIP-764) of PW ASB
No. A6104, Revision 3, dated June 16, 1994, as follows:
(1) Initially inspect the front compressor fan hub at the next
shop visit after the effective date of this AD, but not later than
the compliance end-date.
(2) Remove front compressor fan hubs from service if cracks are
found during the inspection process and replace with a serviceable
hub.
(3) Shotpeen the front compressor fan hubs that pass the
inspection requirements specified in paragraph (b)(1) of this AD, in
accordance with Appendix B of PW ASB No. A6104, Revision 3, dated
June 16, 1994, prior to returning the hub to service.
(4) Thereafter, upon accumulating 2,500 addition CIS since the
last inspection, inspect, shotpeen, and remove from service, if
necessary, front compressor fan hubs that are not reinstalled in the
No. 2 position on Boeing 727 aircraft, in accordance with Appendix
A, Appendix B, and Attachment 1 (NDIP-764) of PW ASB No. A6104,
Revision 3, dated June 16, 1994, when the front compressor fan hub
is accessible at the detail level in the shop.
(5) Thereafter, inspect, shotpeen, and remove from service, if
necessary, front compressor fan hubs that are reinstalled in the No.
2 position of Boeing 727 aircraft after the effective date of this
AD in accordance with paragraph (a)(5) of this AD.
(c) Inspect and shotpeen front compressor fan hubs that were
inspected and shotpeened in accordance with Appendix A, Appendix B,
and Attachment 1 (NDIP-764) of PW ASB No. 6104, dated December 21,
1992, PW ASB No. 6104, Revision 1, dated May 21, 1993, or PW ASB No.
6104, Revision 2, date June 18, 1993, prior to the effective date of
this AD in accordance with paragraphs (a)(5) or (b)(4) of this AD,
as applicable.
(d) For the purpose of this AD, the compliance end-date
referenced in paragraphs (a)(1) and (b)(1) of this AD is defined as
December 31, 1999, or 6,000 TPC after the effective date of this AD,
whichever occurs later.
(e) For the purpose of this AD, a shop visit is defined as an
engine removal for engine maintenance that cannot be performed while
installed in the aircraft, and that entails separation of pairs of
mating (lettered) engine flanges or the removal of a compressor
disk, hub, or spool, or removal of a turbine disk.
(f) For the purpose of this AD, accessibility of a front
compressor fan hub at the detail level in the shop is defined as
engine maintenance that entails separation of the front compressor
fan hub from the front compressor and removal of the fan blades.
(g) Report the front compressor fan hub part number, total time,
and total cycles in service for each hub that passes the inspections
defined in this AD, within 60 days after the inspection, to the
Manager, Engine Certification Office, Engine and Propeller
Directorate, Aircraft Certification Service, FAA, 12 New England
Executive Park, Burlington, Massachusetts, 01803-5299; fax (617)
238-7199. For any hub that is found cracked, submit the information
requested in paragraph B of Part 4, of the Accomplishment
Instructions of PW ASB No. 6104, Revision 3, dated June 16, 1994,
within 60 days after the inspection to the Manager, Engine
Certification Office, at the address identified above. The reporting
requirements of this AD terminate one year after the effective date
of this AD. Information collection requirements contained in this
regulation have been approved by the Office of Management and Budget
(OMB) under the provision of the Paperwork Reduction Act of 1980 (44
U.S.C. 3501-3520) and have been assigned OMB Control Number 2120-
0056.
(h) 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 appropriate 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.
(i) 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. [[Page 27023]]
(j) The modification and repair shall be done in accordance with
the following service document:
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Document No. Pages Revision Date
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PW ASB No. A6104 including Appendix A, and 2, 6............................ 1 May 21, 1993.
Appendix B.
1, 3, 4, 5, 7-12................ 3 June 16, 1994.
Total pages: 12
PW ASB No. A6104 with Attachment 1 NDIP-764 1-14............................ ........... Dec. 8, 1992.
Total pages: 14
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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, Materials
Engineering. 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.
(k) This amendment becomes effective on July 21, 1995.
Issued in Burlington, Massachusetts on May 11, 1995.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 95-12328 Filed 5-18-95; 8:45 am]
BILLING CODE 4910-13-U
