[Federal Register Volume 60, Number 203 (Friday, October 20, 1995)]
[Proposed Rules]
[Pages 54203-54205]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-25994]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-ANE-49]


Airworthiness Directives; Pratt & Whitney JFTD12A Series and T73 
Series Turboshaft 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 (PW) JFTD12A 
series and T73 series turboshaft engines. This proposal would require 
initial and repetitive fluorescent penetrant inspections (FPI) of 
compressor hubs, disks, spacers, and bolted on (rotating) airseals for 
cracks, and replacement, if necessary, with serviceable parts. This 
proposal is prompted by reports of extensive compressor rotor part 
cracking. The actions specified by the proposed AD are intended to 
prevent disk rupture, an uncontained engine failure, and possible 
damage to the helicopter.

DATES: Comments must be received by December 19, 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. 94-ANE-49, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location between 8:00 a.m. and 4:30 p.m., Monday through Friday, 
except Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108. 
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: Barbara Caufield, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7146, fax (617) 238-7199. 

[[Page 54204]]


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 94-ANE-49.'' 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. 94-ANE-49, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    The Federal Aviation Administration (FAA) has received reports of 
cracked compressor hubs, disks, spacers, and bolted on (rotating) 
airseals installed on Pratt & Whitney (PW) Models JFTD12A-4A and -5A 
turboshaft engines. These cracked components were found during overhaul 
type inspections performed at intervals less than the current engine 
overhaul interval. Laboratory analysis of several parts from three of 
these engines has detected a similar pattern of high cycle fatigue 
cracking from multiple origins in compressor disk tierod and blade 
attachment pin holes, spacer tierod and lightening holes, and airseal 
tierod and lightening holes. This condition, if not corrected, could 
result in disk rupture, an uncontained engine failure, and possible 
damage to the helicopter.
    The FAA has also determined that there are engines and aircraft 
operating under Restricted Category that are identical to the 
commercial PW JFTD12A series engines and Sikorsky S-64 series 
helicopters, however, these retain their military designations, T73 
series engines and CH-54 series helicopters. The T73 series engines are 
subject to the same unsafe condition as the PW JFTD12 series engines, 
and, therefore, are included in this AD.
    The FAA has reviewed and approved the technical contents of PW 
Alert Service Bulletin (ASB) No. 5856, Revision 1, dated December 13, 
1991, that describes procedures for initial and repetitive fluorescent 
penetrant inspections (FPI) of compressor hubs, disks, spacers, and 
bolted on (rotating) airseals for cracks, and replacement, if 
necessary, with serviceable parts.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require initial and repetitive FPI of compressor 
hubs, disks, spacers, and bolted on (rotating) airseals for cracks, and 
replacement, if necessary, with serviceable parts. The actions would be 
required to be accomplished in accordance with the alert service 
bulletin described previously.
    There are approximately 120 engines of the affected design in the 
worldwide fleet. The FAA estimates that 47 engines installed on 
aircraft of U.S. registry would be affected by this proposed AD, that 
it would take approximately 140 work hours per engine to accomplish the 
proposed actions, and that the average labor rate is $60 per work hour. 
Required parts would cost approximately $40,670 per engine. Based on 
these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $2,306,290.
    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. 94-ANE-49.

    Applicability: Pratt & Whitney Models JFTD12A-4A and -5A, and 
T73-P-1 and -P-700 turboshaft engines, installed on but not limited 
to Sikorsky S-64 series and CH-54 series helicopters.

    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 (d) 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 disk rupture, an uncontained engine failure, and 
possible damage to the helicopter, accomplish the following:
    (a) Perform a fluorescent penetrant inspection (FPI) of 
compressor hubs, disks, spacers, and bolted on (rotating) airseals 
for cracks in accordance with PW Alert Service 

[[Page 54205]]
Bulletin (ASB) No. 5856, Revision 1, dated December 13, 1991, as 
follows:
    (1) Prior to further flight, for engines that equal or exceed 
2,200 hours time in service (TIS) since last FPI of affected parts 
on the effective date of this airworthiness directive (AD).
    (2) At or before 2,200 hours TIS since last FPI of affected 
parts on the effective date of this AD, for engines that equal or 
exceed 1,500 hours TIS but have less than 2,200 hours TIS since last 
FPI of affected parts on the effective date of this AD.
    (3) At or before 1,500 hours TIS since last FPI of affected 
parts on the effective date of this AD, for engines that have less 
than 1,500 hours TIS since last FPI of affected parts on the 
effective date of this AD.
    (4) Prior to further flight, remove cracked compressor hubs, 
disks, spacers, and bolted on (rotating) airseals, and replace with 
serviceable parts.
    (b) Thereafter, except for engines described in paragraph (c) of 
this AD, perform repetitive FPI of affected parts for cracks at 
intervals not to exceed 1,500 hours TIS since last FPI in accordance 
with PW ASB No. 5856, Revision 1, dated December 13, 1991.
    (c) For all engines inspected in accordance with paragraph (a) 
or (b) of this AD that have zero time second and third stage 
compressor disks installed after the effective date of this AD, 
perform the next FPI of affected parts at or before 3,000 hours TIS 
since the last FPI performed in accordance with paragraph (a) or (b) 
of this AD, and thereafter perform repetitive FPI of affected parts 
for cracks at intervals not to exceed 1,500 hours TIS since the last 
FPI, in accordance with PW ASB No. 5856, Revision 1, dated December 
13, 1991.
    (d) 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.

    (e) 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 11, 1995.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 95-25994 Filed 10-19-95; 8:45 am]
BILLING CODE 4910-13-P