[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]
-----------------------------------------------------------------------
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).
-----------------------------------------------------------------------
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