[Federal Register Volume 77, Number 165 (Friday, August 24, 2012)]
[Rules and Regulations]
[Pages 51459-51462]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-20842]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2012-0079; Directorate Identifier 2012-NE-06-AD;
Amendment 39-17148; AD 2012-16-01]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney Division Turbofan
Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: We are adopting a new airworthiness directive (AD) for Pratt &
Whitney Division PW4052, PW4152, PW4056, PW4156A, PW4060, PW4060A,
PW4060C, PW4062, PW4062A, PW4158, PW4460, PW4462, PW4164, PW4164C,
PW4164C/B, PW4168, and PW4168A turbofan engines with certain high-
pressure turbine (HPT) stage 1 front hubs installed. This AD was
prompted by Pratt & Whitney's updated low-cycle-fatigue analysis that
indicated certain HPT stage 1 front hubs could initiate a crack prior
to the published life limit. This AD requires removing the affected HPT
stage 1 front hubs from service using a drawdown plan. We are issuing
this AD to prevent failure of the HPT stage 1 front hub, which could
lead to an uncontained engine failure and damage to the airplane.
DATES: This AD is effective September 28, 2012.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in the AD as of September 28,
2012.
ADDRESSES: For service information identified in this AD, contact Pratt
& Whitney, 400 Main St., East Hartford, CT 06108; phone: 860-565-7700;
fax: 860-565-1605. You may view this service information at the FAA,
Engine & Propeller Directorate, 12 New England Executive Park,
Burlington, MA. For information on the availability of this material at
the FAA, call 781-238-7125.
Examining the AD Docket
You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this AD, the regulatory evaluation,
any comments received, and other information. The address for the
Docket Office (phone: 800-647-5527) is Document Management Facility,
U.S. Department of Transportation, Docket Operations, M-30, West
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE.,
Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: James Gray, Aerospace Engineer, Engine
Certification Office, FAA, 12 New England Executive Park, Burlington,
MA; phone: 781-238-7742; fax: 781-238-7199; email:
james.e.gray@faa.gov.
[[Page 51460]]
SUPPLEMENTARY INFORMATION:
Discussion
We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to include an AD that would apply to the specified products.
That NPRM published in the Federal Register on March 23, 2012 (77 FR
16967). That NPRM proposed to require removing the affected HPT stage 1
front hubs from service using a drawdown plan.
Comments
We gave the public the opportunity to participate in developing
this AD. The following presents the comments received on the proposal
and the FAA's response to each comment.
Support for the NPRM
One commenter, The Boeing Company, supported the contents of the
proposed AD (77 FR 16967, March 23, 2012), as written.
Request To Modify Applicability
Commenters United Airlines, United Parcel Service Co. (UPS), Pratt
& Whitney (P&W), and MNG Airlines requested that part numbers (P/Ns)
52L301 and 51L201-021 be added to the applicability paragraphs (c)(1)
and (c)(2) of the proposed AD (77 FR 16967, March 23, 2012). The
commenters noted that the applicability of the proposed AD is
inconsistent since it includes some assembly P/Ns and some detail P/Ns.
We agree. We revised the applicability paragraphs of this AD to
include the referenced P/Ns for consistency.
Request To Change Compliance Time
Commenters UPS, MNG Airlines, and Onur Air requested that the
compliance time be changed to ``at next piece-part exposure after the
effective date of this AD or before accumulating the number of cycles
listed in this AD, whichever occurs later.'' MNG Airlines indicated
that its engines would lose 1,382 flight cycles, which would cost more
than $1,000,000 and force early shop visits. Onur Air noted that its
engines would lose 1,300 cycles and it would cause stub life problems
on other life limited parts. UPS also expressed its concern over the
increased shop burden from a hub life reduction.
We do not agree. We determined that removal of the HPT stage 1
front hubs according to the compliance times in paragraph (f) of this
AD provides an acceptable level of safety for the fleet. This
acceptable level of safety would not be maintained if all HPT stage 1
front hubs were allowed to remain in service until the next piece-part
exposure above the number of cycles listed in this AD. For this reason,
we also cannot adjust the compliance time to account for potential stub
life problems that might occur in the other rotors. We did not change
the AD.
Request To Reference the PW4000 Engine Manual Chapter 05 Life Limits
Commenters MNG Airlines and P&W requested that the phrase ``former
life limits cannot be exceeded'' be added to compliance paragraphs
(f)(1)(ii) and (f)(2)(ii) of the proposed AD (77 FR 16967, March 23,
2012), or that some other reference to the PW4000 Engine Manual Chapter
05 life limits be added when the stage 1 front hub is operating during
the 1,000 cycle drawdown. United commented that a reference to the
reduced life limits be included in Chapter 05 of the Airworthiness
Limitations Section (ALS) of the PW4000 Engine Manual.
We do not agree. The Chapter 05 life limits cannot be exceeded. For
those hubs beneath the Chapter 05 life limit, this AD requires removal
according to the drawdown schedule in the AD, which is before the
Chapter 05 limit is reached. This AD's requirements are independent
from the Chapter 05 life limits in the ALS of the PW4000 Engine Manual.
We did not change the AD.
Request Revisions to Service Information To Be Incorporated by
Reference
P&W, UPS, and United requested revisions to the service information
that is incorporated by reference in the AD. P&W requested that the AD
reference the new P&W Alert Service Bulletin (ASB) No. PW4ENG A72-821,
dated July 6, 2012 and P&W ASB No. PW4G-100-A72-246, dated June 28,
2012, which address the unsafe condition and contain the affected part
numbers by serial number for the PW4000-94'' and PW4000-100'' engines.
UPS also asked that the AD be revised to note that any subsequent
revision of the service bulletin (SB) can be used for compliance.
We agree in part. Our proposed AD (77 FR 16967, March 23, 2012),
referenced the P/N-serial number (S/N) tables of affected parts in the
old SBs. We agree that we should use the new P&W SBs. We changed
paragraph (c) of this AD to incorporate the P/N-S/N tables from the new
P&W ASBs, specifically from P&W ASB No. PW4ENG A72-821, dated July 6,
2012 and P&W ASB No. PW4G-100-A72-246, dated June 28, 2012.
We disagree that the AD should be revised to incorporate future
revisions of an ASB because we do not know the contents of SBs not yet
published. We did not change the AD based on UPS's comment.
Request To Modify Compliance Wording
P&W requested that the phrase ``or at the next piece-part exposure
after the effective date of this AD, whichever occurs first'' be
removed from the compliance paragraphs (f)(1)(ii) and (f)(2)(ii). P&W
indicated that, based on the proposed AD, operators may not be able to
run HPT stage 1 front hubs, identified in paragraphs (c)(1)(i) and
(c)(1)(ii), that are exposed at piece-part between 17,000 and 18,000
cycles-since-new (CSN) and HPT stage 1 front hubs, identified in
paragraphs (c)(2) and (c)(3), that are exposed between 12,700 and
13,700 CSN, to the full 1,000 cycle drawdown.
We partially agree. We agree that the AD if adopted as proposed
could have forced removal of HPT stage 1 front hubs prior to reaching
18,000 CSN and 13,700 CSN, respectively. We disagree that we should
remove the at piece-part exposure wording from paragraphs (f)(1)(ii)
and (f)(2)(ii) of the AD, because HPT stage 1 front hubs that are
exposed at piece-part after 18,000 CSN and 13,700 CSN should not go
back into service, even if they have not accumulated an additional
1,000 cycles in service. We therefore, revised paragraphs (f)(1)(ii)
and (f)(2)(ii) of the proposed AD (77 FR 16967, March 23, 2012), to
clarify that these HPT stage 1 front hubs should be removed at the next
piece-part exposure above 18,000 CSN and 13,700 CSN, respectively,
rather than at the next piece-part exposure after the effective date of
the AD. This change is consistent with the installation prohibition for
HPT stage 1 front hubs in paragraph (g) of this AD.
Request for Allowance for Mixed-Model Management
United asked that the AD include an allowance for mixed-model
management.
We do not agree. The AD does not restrict use of mixed-model
management. If an operator uses mixed-model management, then 18,000 CSN
and 13,700 CSN should be used in the calculation for the respective
engine models included in paragraph (c) of this AD. We did not change
the AD.
Request To Add Credit for Prior Compliance
FedEx Express (FedEx) asked that the AD include credit for
compliance to prior SBs.
[[Page 51461]]
We do not agree. Operators can take credit for previous actions
based on paragraph (e) of this AD. We did not change the AD.
Request To Clarify Requirements for P/N 51L901
FedEx asked that the AD requirements for stage 1 front hub, P/N
51L901, be clarified. FedEx claimed that the relevant service
information section of the AD and its applicability are contradictory.
We do not agree. We reviewed the P/N references and find no
contradictions between the two sections. We did not change the AD.
Revision to Cost of Compliance
In reviewing our cost of compliance estimate made in the NPRM (77
FR 16967, March 23, 2012), we found that our estimate was wrong.
Specifically, we found that we based our estimate on the number of
engines installed on airplanes worldwide rather than just on the U.S.
fleet. Therefore, we changed our estimate to reflect U.S. operators
only. This change reduced the number of engines affected from 954 to
289 and the total cost estimate from $23,049,537 to $6,981,578.
Conclusion
We reviewed the relevant data, considered the comments received,
and determined that air safety and the public interest require adopting
the AD with the changes described previously. We also determined that
these changes will not increase the economic burden on any operator nor
increase the scope of the AD.
Costs of Compliance
We estimate that this AD would affect 289 engines installed on
airplanes of U.S. registry. About 183 engines use a 20,000 CSN life
limit for the HPT stage 1 front hub. For these engines, we estimate the
lost part life to have a value of about $25,400 per engine. About 106
engines use a 15,000 CSN life limit. For these engines, we estimate the
lost life to have a value of about $22,013 per engine. Based on these
figures, we estimate the total cost of the AD to U.S. operators is
$6,981,578.
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. Subtitle VII: Aviation Programs,
describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701: ``General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.
Regulatory Findings
This AD will not have federalism implications under Executive Order
13132. This AD will not have a substantial direct effect 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.
For the reasons discussed above, I certify that this AD:
(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),
(3) Will not affect intrastate aviation in Alaska, and
(4) 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
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]
0
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive (AD):
2012-16-01 Pratt & Whitney Division: Amendment 39-17148; Docket No.
FAA-2012-0079; Directorate Identifier 2012-NE-06-AD.
(a) Effective Date
This AD is effective September 28, 2012.
(b) Affected ADs
None.
(c) Applicability
This AD applies to the following Pratt & Whitney Division
turbofan engines:
(1) PW4052, PW4152, and PW4056 turbofan engines, including
models with any dash number suffix, with a high-pressure turbine
(HPT) stage 1 front hub part number (P/N) listed in Table 1 to
paragraph (c) of this AD installed.
(2) PW4156A, PW4060, PW4060A, PW4060C, PW4062, PW4062A, PW4158,
PW4460, and PW4462 turbofan engines, including models with any dash
number suffix, with an HPT stage 1 front hub P/N listed in Table 1
to paragraph (c) of this AD installed.
Table 1 to Paragraph (c)
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P/N 51L601........................ All serial numbers (S/Ns).
P/N 52L401........................ With a S/N not listed in Table 5 of
the Accomplishment Instructions of
Pratt & Whitney Alert Service
Bulletin (ASB) No. PW4ENG A72-821,
dated July 6, 2012.
P/N 51L201, P/N 51L201-001, P/N All S/Ns.
51L201-021.
P/N 51L901, P/N 52L301............ With an S/N not listed in Table 7 of
the Accomplishment Instructions of
Pratt & Whitney ASB No. PW4ENG A72-
821, dated July 6, 2012.
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(3) PW4164, PW4164C, PW4164C/B, PW4168, and PW4168A turbofan
engines with an HPT stage 1 front hub, P/N 51L901, installed with an
S/N not listed in Table 3 of the Accomplishment Instructions of
Pratt & Whitney ASB No. PW4G-100-A72-246, dated June 28, 2012.
(d) Unsafe Condition
This AD was prompted by Pratt & Whitney's updated low-cycle-
fatigue analysis that indicated certain HPT stage 1 front hubs could
initiate a crack prior to the published
[[Page 51462]]
life limit. This AD requires removing the affected HPT stage 1 front
hubs from service using a drawdown plan. We are issuing this AD to
prevent failure of the HPT stage 1 front hub, which could lead to an
uncontained engine failure and damage to the airplane.
(e) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(f) Removal of HPT Stage 1 Front Hubs From Service
(1) For HPT stage 1 front hubs listed in paragraph (c)(1) of
this AD, do the following:
(i) If the HPT stage 1 front hub has accumulated 17,000 or fewer
cycles-since-new (CSN) on the effective date of this AD, remove the
HPT stage 1 front hub from service before accumulating 18,000 CSN.
(ii) If the HPT stage 1 front hub has accumulated more than
17,000 CSN on the effective date of this AD, remove the HPT stage 1
front hub from service before accumulating an additional 1,000
cycles-in-service (CIS) or at the next piece-part exposure above
18,000 CSN, whichever occurs first.
(2) For HPT stage 1 front hubs listed in paragraphs (c)(2) and
(c)(3) of this AD, do the following:
(i) If the HPT stage 1 front hub has accumulated 12,700 or fewer
CSN on the effective date of this AD, remove the HPT stage 1 front
hub from service before accumulating 13,700 CSN.
(ii) If the HPT stage 1 front hub has accumulated more than
12,700 CSN on the effective date of this AD, remove the HPT stage 1
front hub from service before accumulating an additional 1,000 CIS
or at the next piece-part exposure above 13,700 CSN, whichever
occurs first.
(g) Installation Prohibition
After the effective date of this AD, do not install into any
engine any HPT stage 1 front hubs listed in paragraph (c)(1) of this
AD that are at piece-part exposure and exceed 18,000 CSN, or any HPT
stage 1 front hubs listed in paragraphs (c)(2) and (c)(3) of this AD
that are at piece-part exposure and exceed 13,700 CSN.
(h) Definition
For the purpose of this AD, piece-part exposure means that the
part is completely disassembled and removed from the engine.
(i) Alternative Methods of Compliance (AMOCs)
The Manager, Engine Certification Office, may approve AMOCs for
this AD. Use the procedures found in 14 CFR 39.19 to make your
request.
(j) Related Information
For more information about this AD, contact James Gray,
Aerospace Engineer, Engine Certification Office, FAA, 12 New England
Executive Park, Burlington, MA; phone: 781-238-7742; fax: 781-238-
7199; email: james.e.gray@faa.gov.
(k) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference (IBR) of the following service
information under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use the following service information to do the
actions required by this AD, unless the AD specifies otherwise:
(i) Pratt & Whitney Alert Service Bulletin (ASB) No. PW4ENG A72-
821, dated July 6, 2012.
(ii) Pratt & Whitney ASB No. PW4G-100-A72-246, dated June 28,
2012.
(3) For service information identified in this AD, contact Pratt
& Whitney, 400 Main St., East Hartford, CT 06108; phone: 860-565-
7700; fax: 860-565-1605.
(4) You may review this service information at the FAA, Engine &
Propeller Directorate, 12 New England Executive Park, Burlington,
MA. For information on the availability of this material at the FAA,
call 781-238-7125.
(5) You may also review the service information that is
incorporated by reference at the National Archives and Records
Administration (NARA). For information on the availability of this
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.
Issued in Burlington, Massachusetts, on July 26, 2012.
Peter A. White,
Manager, Engine & Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 2012-20842 Filed 8-23-12; 8:45 am]
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