[Federal Register Volume 62, Number 22 (Monday, February 3, 1997)]
[Rules and Regulations]
[Pages 4900-4902]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-1700]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-ANE-49; Amendment 39-9898; AD 97-02-13]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney JFTD12A Series and T73 
Series Turboshaft Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to Pratt & Whitney JFTD12A series and T73 series turboshaft 
engines, that requires 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 amendment is prompted by reports of extensive 
compressor rotor part cracking. The actions specified by this AD are 
intended to prevent disk rupture, an uncontained engine failure, and 
possible damage to the aircraft.

DATES: Effective April 4, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of April 4, 1997.

ADDRESSES: The service information referenced in this AD may be 
obtained from Pratt & Whitney, Publications Department, Supervisor 
Technical Publications Distribution, M/S 132-30, 400 Main St., East 
Hartford, CT 06108; telephone (860) 565-7700, fax (860) 565-4503. 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: 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.

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) JFTD12A 
series and T73 series turboshaft engines was published in the Federal 
Register on October 20, 1995 (60 FR 54203). That action proposed to 
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, in 
accordance with PW Alert Service Bulletin (ASB) No. 5856, Revision 1, 
dated December 13, 1991.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

[[Page 4901]]

    One commenter states specific part numbers (P/N's) for all parts 
affected by the AD should be added to the compliance section, in order 
to eliminate the need to revise the AD if future part modifications 
occur that negate the necessity for inspection. The FAA does not 
concur. As written, the AD applies to all JFTD12A-4A, -5A, T73-P-1, and 
-P-700 engines regardless of the hardware installed. The note following 
the applicability paragraph clarifies that if a future part 
modification occurs, the operator must request an alternative method of 
compliance in order to comply with the AD. The operator cannot make the 
determination to not comply with the AD independently. There may not be 
a need to revise or supersede the AD since an alternative method of 
compliance may be available.
    The commenter also states that a specific inspection of the third 
stage disk tiebolt holes utilizing eddy current techniques in 
accordance with a Pratt & Whitney approved procedure must be 
accomplished in addition to FPI. Cracks have only occurred in the third 
stage disk tiebolt holes and the second stage disk blade pin holes. The 
commenter takes specific exception to the use of FPI to detect these 
cracks as they have significant experience that the utilization of the 
highest sensitivity penetrant required by Pratt & Whitney does not 
consistently identify cracked disks. The FAA does not concur. The risk 
analysis used to determine the AD compliance interval takes into 
account the reliability of the FPI, including the probability that an 
FPI inspection will not identify all cracks. The FAA has determined 
that FPI is adequate for detecting cracks in the third stage disk 
tiebolt holes and second stage disk blade pin holes.
    The commenter also states that the AD should only address second 
and third stage disks and allow all the other parts to remain at the 
overhaul inspection interval of 3,000 hours time in service (TIS). 
Cracks have been found only in the third stage disk tiebolt holes and 
the second stage disk blade pin holes. There has never been a crack 
found in first stage or fourth through ninth stage disks. Therefore, 
continued inspection of all other parts at 1,500 hour TIS intervals is 
unnecessary and an economic burden, especially due to the complexity of 
deblading all nine stages of compressor disks. The FAA concurs in part. 
The FAA agrees that the inspection of the first stage disk and fourth 
through ninth stage disks may be accomplished at a 3,000 hour TIS 
overhaul interval; this final rule has been revised accordingly. 
However, inspection of all other parts, including second and third 
stage disks, hubs, spacers and bolted on (rotating) airseals, must 
still be accomplished at 1,500 hour TIS intervals. The FAA has revised 
the AD accordingly.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest 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.
    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 will be affected by this AD, that it will 
take approximately 140 work hours per engine to accomplish the required 
actions, and that the average labor rate is $60 per work hour. Required 
parts will cost approximately $40,670 per engine. Based on these 
figures, the total cost impact of the AD on U.S. operators is estimated 
to be $2,306,290.
    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

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

97-02-13  Pratt & Whitney: Amendment 39-9898. Docket 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 aircraft.

    Note 1: 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 request 
approval for an alternative method of compliance in accordance with 
paragraph (e) of this AD. The request should include an assessment 
of the effect of the modification, alteration, or repair on the 
unsafe condition addressed by this AD; and, if the unsafe condition 
has not been eliminated, the request should include specific 
proposed actions to address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent disk rupture, an uncontained engine failure, and 
possible damage to the aircraft, accomplish the following:
    (a) Perform a fluorescent penetrant inspection (FPI) of 
compressor hubs, second stage and third stage disks, spacers, and 
bolted on (rotating) airseals for cracks in accordance with PW Alert 
Service 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, 
second and third stage disks, spacers, and bolted on (rotating) 
airseals, and replace with serviceable parts.
    (b) Thereafter, except for engines described in paragraphs (c) 
and (d) of this AD, perform repetitive FPI of affected parts for 
cracks at

[[Page 4902]]

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) Perform FPI of compressor first stage and fourth through 
ninth stage disks for cracks, in accordance with PW ASB No. 5856, 
Revision 1, dated December 13, 1991, as follows:
    (1) At or before 3,000 hours TIS since last FPI of affected 
parts on the effective date of this AD.
    (2) Thereafter, perform repetitive FPI of affected parts for 
cracks at intervals not to exceed 3,000 hours TIS since last FPI, in 
accordance with PW ASB No. 5856, Revision 1, dated December 13, 
1991.
    (3) Prior to further flight, remove cracked compressor first 
stage and fourth through ninth stage disks, and replace with 
serviceable parts.
    (d) For all engines inspected in accordance with paragraphs (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. Prior to further flight, remove cracked compressor disks, 
and replace with serviceable parts.
    (e) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    (f) 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.
    (g) The actions required by this AD shall be done in accordance 
with the following PW ASB:

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          Document No.            Pages    Revision          Date       
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No. 5856.......................     1-3  1..........  December 13, 1991.
                                      4  Original...  June 16, 1989.    
                                    5-7  1..........  December 13, 1991.
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Total pages: 7.

    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, Publications 
Department, Supervisor Technical Publications Distribution, M/S 132-
30, 400 Main St., East Hartford, CT 06108; telephone (860) 565-7700. 
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.
    (h) This amendment becomes effective on April 4, 1997.

    Issued in Burlington, Massachusetts, on January 13, 1997.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 97-1700 Filed 1-31- 97; 8:45 am]
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