[Federal Register Volume 60, Number 199 (Monday, October 16, 1995)]
[Proposed Rules]
[Pages 53554-53556]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-25565]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-ANE-37]


Airworthiness Directives; Pratt & Whitney PW2000 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 Pratt & Whitney PW2000 series 
turbofan engines. This proposal would require a reduction in the cyclic 
service life limit for hubs, disks, airseals, blade retaining plates, 
and airsealing ring supports on certain high pressure turbines (HPT) 
and low pressure turbines (LPT), and provide for optional inspections 
for cracks or rework of certain HPT and LPT hardware in order to retain 
the original, higher cyclic service life limit for these components. 
This proposal is prompted in part by new temperature data from engine 
testing, which were used in recalculating stress levels, and resulted 
in a change to the calculated cyclic service life limit. The actions 
specified by the proposed AD are intended to prevent HPT or LPT 
failure, which may result in an uncontained engine failure and possible 
damage to the aircraft.

DATES: Comments must be received by December 15, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 95-ANE-37, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location between 8 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, Technical Publications Department, M/S 
132-30, 400 Main Street, East Hartford, CT 06108. This information may 
be examined at the FAA, New England Region, Office of the Assistant 
Chief Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: John Fisher, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7149, fax (617) 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 in triplicate 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 95-ANE-37.'' 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 Assistant Chief Counsel, 
Attention: Rules Docket No. 95-ANE-37, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    The Federal Aviation Administration (FAA) has received updated high 
pressure turbine (HPT) and low pressure turbine (LPT) life limited part 
data for Pratt & Whitney PW2000 series turbofan engines, derived from 
the manufacturer's review of turbine temperature data. The updated data 
and resulting part life analysis indicate that the service cyclic life 
limits must be reduced for certain HPT and LPT hubs, disks, airseals, 
blade retaining plates, and airsealing ring supports. This condition, 
if not corrected, could result in HPT or LPT failure, which may result 
in an uncontained engine failure and possible damage to the aircraft.
    The FAA has reviewed and approved the technical contents of Pratt & 
Whitney PW2000 Engine Manual, Part Number (P/N) 1A6231, Sections 72-52-
00, 72-53-00, and 05-10-00, which lists the reduced service cyclic life 
limits for affected parts identified by P/N, and describes procedures 
for optional inspections for cracks or rework of certain HPT and LPT 
hardware in order to retain the original, higher cyclic service life 
limit for these components; PW Service Bulletin (SB) No. 72-82, 
Revision 4, dated June 18, 1987, that describes rework and 
reidentification of the 1st stage HPT blade retaining plates to extend 
part life from 5,000 total part cycles (TPC) to 15,000 TPC; PW Alert 
Service Bulletin (ASB) No. 72-228, Revision 4, dated November 9, 1988, 
that describes inspections and rework of the 2nd stage HPT blade 
retaining plates in order to attain their respective published part 
lives; PW Alert SB No. 72-450, Revision 5, dated May 28, 1994, that 
describes inspections, rework, and reidentification of the 2nd stage 
HPT hubs to extend part life from 6,000 TPC to 15,000 TPC; PW SB No. 
72-501, dated September 30, 1993, that describes inspections, rework, 
and reidentification of the 2nd stage HPT blades and inspection and 
reidentification of 2nd stage HPT hubs to extend hub life from 7,500 
TPC to 15,000 TPC; PW ASB No. 72-220, Revision 4, dated September 20, 
1989, that describes rework of the HPT lenticular seal to extend part 
life from 4,000 TPC to 15,000 TPC; and PW SB No. 72-233, Revision 3, 
dated May 30, 1989, that describes rework and identification of the HPT 
lenticular seal to extend part life from 4,000 TPC to 15,000 TPC.
    Since an unsafe condition has been identified that is likely to 
exist or 

[[Page 53555]]
develop on other engines of this same type design, the proposed AD 
would require a reduction in the cyclic service life limit for hubs, 
disks, airseals, blade retaining plates, and airsealing ring supports 
on certain HPT and LPT, and provide for optional inspections for cracks 
or rework of certain HPT and LPT hardware in order to retain the 
original, higher cyclic service life limit for these components.
    There are approximately 650 engines of the affected design in the 
worldwide fleet. The FAA estimates that 600 engines installed on 
aircraft of U.S. registry would be affected by this proposed AD, and 
that no additional labor costs would be incurred by the fleet since 
inspection and replacement intervals fall within the normal overhaul 
periods. Therefore, the FAA has determined that there would be no 
additional cost impact on U.S. operators due to sufficient time to 
schedule shop visits.
    The regulations proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    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), 40101, 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Pratt & Whitney: Docket No. 95-ANE-37.

    Applicability: Pratt & Whitney Models PW2037, PW2037(M), PW2040, 
PW2240, and PW2337 turbofan engines installed on but not limited to 
Boeing 757 series and Ilyushin IL96 series aircraft.

    Note: This 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 (o) to 
request approval from the 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 high pressure turbine (HPT) or low pressure turbine 
(LPT) failure, which may result in an uncontained engine failure and 
possible damage to the aircraft, accomplish the following:
    (a) Remove from service 1st stage HPT disks, Part Number (P/N) 
1A5301, prior to exceeding 5,000 total part cycles (TPC), if 
installed with blade retaining plate, P/N 1A6998, and replace with 
serviceable parts. If blade retaining plate, P/N 1A6998, has not 
been installed on disk, P/N 1A5301, the disk may accumulate 15,000 
TPC prior to removal from service.
    (b) Remove from service 1st stage HPT blade retaining plates, P/
N 1A6998, prior to exceeding 5,000 TPC, and replace with serviceable 
parts. If rework is accomplished prior to exceeding 5,000 TPC in 
accordance with the Accomplishment Instructions of PW Service 
Bulletin (SB) No. 72-82, Revision 4, dated June 18, 1987, and 
reidentified as assembly P/N 1B2373, the blade retaining plate may 
accumulate 15,000 TPC prior to removal from service.
    (c) Remove from service 2nd stage HPT blade retaining plates, P/
N 1B0450, prior to exceeding 7,000 TPC, and replace with serviceable 
parts.
    (d) Remove from service 2nd stage HPT blade retaining plates, P/
N 1B0945 (assembly P/N 1B0947), and replace with serviceable parts, 
in accordance with the Accomplishment Instructions of PW Alert 
Service Bulletin (ASB) No. 72-228, Revision 4, dated November 9, 
1988, as follows:
    (1) Prior to exceeding 5,000 TPC, for retaining plates that have 
not been inspected in accordance with the Accomplishment 
Instructions of the above ASB prior to 3,000 TPC.
    (2) Prior to exceeding 8,000 TPC, for retaining plates that have 
been inspected in accordance with the Accomplishment Instructions of 
the above ASB prior to 3,000 TPC.
    (e) Remove from service 2nd stage HPT hubs, P/N's 1A8302, 
1B1002, 1B1202, and 1B4902 prior to exceeding 6,000 TPC, and replace 
with serviceable hubs. Hubs may accumulate 15,000 TPC prior to 
removal from service if they are inspected at intervals that are not 
more than 6,000 TPC, in accordance with the Accomplishment 
Instructions of PW Alert SB No. 72-450, Revision 5, dated May 28, 
1994.
    (f) Remove from service 2nd stage HPT hubs, P/N 1B6602, prior to 
exceeding 7,500 TPC, and replace with serviceable hubs. Hubs may 
accumulate 15,000 TPC prior to removal from service if hub 
assemblies are inspected prior to 7,500 TPC to verify scarf cut 
blades are installed and to inspect the blade platform rail fillet 
radii dimensions, in accordance with the Accomplishment Instructions 
of PW SB No. 72-501, dated September 30, 1993. Hub assemblies found 
with non-scarf cut blades must be reinspected at intervals not to 
exceed 6,000 TPC since last inspection. Blades found with under 
minimum radii dimensions must be scrapped.
    (g) Remove from service HPT lenticular airseal, P/N 1A8209, 
prior to exceeding 4,000 TPC, and replace with serviceable airseals. 
Airseals may accumulate 15,000 TPC prior to removal from service if:
    (1) Inspected prior to exceeding 4,000 TPC, and thereafter 
inspected at intervals not to exceed 250 cycles in service since 
last inspection, in accordance with Compliance Paragraph E of the 
Accomplishment Instructions of PW ASB No. 72-220, Revision 4, dated 
September 20, 1989; or
    (2) The 2nd stage HPT case and vane assembly is reworked (pre-
trench) and reidentified prior to exceeding 4,000 TPC in accordance 
with the Accomplishment Instructions of PW SB No. 72-233, Revision 
3, dated May 30, 1989.
    (h) For PW2037, PW2037(M), and PW2337 model engines, remove from 
service 4th stage LPT disks, P/N's 8A1024, 8A1534, and 8A2137 prior 
to exceeding 17,000 TPC, and replace with serviceable disks.
    (i) For PW2040 and PW2240 model engines, remove from service 4th 
stage LPT disks, P/N's 8A1534 or 8A2137, prior to exceeding 15,000 
TPC, and replace with serviceable disks.
    (j) Remove from service 3rd stage LPT airsealing ring supports, 
P/N 8A1783, and replace with serviceable parts, as follows:
    (1) For PW2040 and PW2240 model engines, prior to exceeding 
15,000 TPC.
    (2) For PW2037, PW2037(M), and PW2337 model engines, prior to 
exceeding 17,000 TPC. Airsealing ring supports may accumulate 20,000 
TPC prior to removal from 

[[Page 53556]]
service if they were fluorescent penetrant inspected in accordance with 
PW2000 Engine Manual, P/N 1A6231.
    (k) For PW2037, PW2037(M), and PW2337 model engines, remove from 
service prior to exceeding 17,000 TPC, and replace with serviceable 
parts, as follows:
    (1) 4th stage LPT airseal, P/N's 8A1014 and 8A1805.
    (2) 5th stage LPT airseal, P/N's 8A1015 and 8A1806.
    (3) 7th stage LPT airseal, P/N's A8A1017, A8A1808, 8A2097, and 
A8A2097.
    (l) Parts listed in paragraph (k) of this AD may accumulate 
20,000 TPC prior to removal from service if they were fluorescent 
penetrant inspected for cracks between 12,000 TPC and 17,000 TPC in 
accordance with Section 72-53-00 of PW2000 Engine Manual, P/N 
1A6231.
    (m) For PW2040 and PW2240 model engines, remove from service 
prior to exceeding 15,000 TPC, and replace with serviceable parts, 
as follows:
    (1) 4th stage LPT airseal, P/N's 8A1014 and 8A1805.
    (2) 5th stage LPT airseal, P/N's 8A1015 and 8A1806.
    (3) 7th stage LPT airseal, P/N's A8A1017, A8A1808, 8A2097, and 
A8A2097.
    (n) Parts listed in paragraph (m) of this AD may accumulate the 
following TPC prior to removal from service if they were fluorescent 
penetrant inspected for cracks between 10,000 TPC and 15,000 TPC in 
accordance with Section 72-53-00 of PW2000 Engine Manual, P/N 
1A6231.
    (1) 4th stage LPT airseal, P/N's 8A1014 and 8A1805, prior to 
exceeding 18,000 TPC.
    (2) 5th stage LPT airseal, P/N's 8A1015 and 8A1806, prior to 
exceeding 19,000 TPC.
    (3) 7th stage LPT airseal, P/N's A8A1017, A8A1808, 8A2097, and 
A8A2097, prior to exceeding 20,000 TPC.
    (o) 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.

    (p) 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.

    Issued in Burlington, Massachusetts, on October 3, 1995.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 95-25565 Filed 10-13-95; 8:45 am]
BILLING CODE 4910-13-U