Airworthiness Directives; Pratt & Whitney Division Turbofan Engines

[Federal Register Volume 79, Number 225 (Friday, November 21, 2014)]
[Rules and Regulations]
[Pages 69369-69372]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-27354]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2013-0072; Directorate Identifier 2013-NE-04-AD; 
Amendment 39-18017; AD 2014-23-01]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Division Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We are superseding airworthiness directive (AD) 2013-15-09 for 
all Pratt & Whitney Division (PW) PW4074, PW4074D, PW4077, PW4077D, 
PW4084D, PW4090, and PW4090-3 turbofan engine models with certain 
second-stage high-pressure turbine (HPT) air seals installed. AD 2013-
15-09 required initial and repetitive inspections for cracks in second-
stage HPT air seals. This new AD expands the applicability of AD 2013-
15-09 to include additional part numbers (P/Ns), requires removal of 
the mating hardware if the second-stage HPT air seal is found with a 
through-crack, and adds a mandatory terminating action. This AD was 
prompted by reports of cracking in the original location on two 
additional P/Ns and reports of through-cracks in a new location in the 
second-stage HPT air seal. We are issuing this AD to prevent failure of 
the second-stage HPT air seal, which could lead to uncontained engine 
failure and damage to the airplane.

DATES: This AD is effective December 26, 2014.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of September 
17, 2013 (78 FR 49111, August 13, 2013).

ADDRESSES: For service information identified in this AD, contact Pratt 
& Whitney Division, 400 Main St., East Hartford, CT 06108; phone: (860) 
565-8770; fax: (860) 565-4503. 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 by searching for and locating Docket No. FAA-2013-
0072; 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: Jo-Ann Theriault, Aerospace Engineer, 
Engine Certification Office, FAA, Engine & Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803; phone: 781-238-7105; 
fax: 781-238-7199; email: [email protected].

SUPPLEMENTARY INFORMATION: 

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to supersede AD 2013-15-09, Amendment 39-17525 (78 FR 49111, 
August 13, 2013), (``AD 2013-15-09''). AD 2013-15-09 applied to all PW 
PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 
turbofan engine models with certain second-stage HPT air seals 
installed. The NPRM published in the Federal Register on June 5, 2014 
(79 FR 32500). The NPRM was prompted by reports of through-cracks in a 
different location on a second-stage HPT air seal, and reports of 
cracking in the original location in two additional second-stage HPT 
air seals. Pratt & Whitney developed a redesigned second-stage

[[Page 69370]]

HPT air seal that corrects the cracking condition in both locations.
    The NPRM proposed to require initial and repetitive inspections for 
cracks in an expanded population of second-stage HPT air seals, and 
removal of air seals that fail inspection. The NPRM also proposed to 
require removal of the mating hardware if the second-stage HPT air seal 
is found with a through-crack, and a mandatory terminating action to 
the repetitive inspection requirements. We are issuing this AD to 
correct the unsafe condition on these products.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the NPRM (79 
FR 32500, June 5, 2014) and the FAA's response to each comment.

Request To Correct P/N

    All Nippon Airways (ANA), Japan Airlines, United Airlines (UA), and 
PW requested that we correct the reference in the NPRM (79 FR 32500, 
June 5, 2014) to the P/N for the second-stage HPT air seal from 50L041 
to 54L041.
    We agree. We corrected the reference to the second-stage HPT air 
seal P/N in this AD.

Request To Include Air Seal Detail P/N

    UA requested that we include the P/N for the air seal detail in 
this AD. UA has observed instances where the air seal detail, P/N 
54L043, is shown as the P/N for the second-stage HPT air seal.
    We disagree. The second-stage HPT air seal is identified as P/N 
54L041. It includes air seal detail, P/N 54L043. This AD applies to the 
entire second-stage HPT air seal, including all of its details. We did 
not change this AD.

Request To Change Compliance Time

    ANA, PW, and UA requested that the compliance interval in paragraph 
(e)(2)(i) of the NPRM (79 FR 32500, June 5, 2014) be increased from 100 
cycles-in-service (CIS) to 1,000 CIS. The commenters indicated that 
this AD should be consistent with AD 2013-15-09, which specifies that 
the eddy current inspection (ECI) or initial fluorescent-penetrant 
inspection (FPI) should be performed within 1,000 cycles after the 
effective date of the AD.
    We agree. Performing an ECI or initial FPI within 1,000 cycles of 
September 17, 2013, the effective date of AD 2013-15-09, maintains an 
acceptable level of safety. We changed paragraph (e)(2)(i) of this AD 
to read: ``Perform an initial eddy current inspection (ECI) for cracks 
within 1,000 cycles-in-service after September 17, 2013, or before 
further flight, whichever occurs later.''

Request To Update Service Information

    ANA and PW asked that we update the reference to the service 
information from PW Service Bulletin (SB) No. PW4G-112-A72-332, 
Revision 2, dated April 9, 2014, to PW SB No. PW4G-112-A72-332, 
Revision 3, dated June 25, 2014.
    We agree. We updated the service information reference in the 
Related Information paragraph in this AD to reflect the most current 
revision of SB No. PW4G-112-A72-332.

Request To Include First-Stage HPT Air Seals

    ANA requested that first-stage HPT air seals be added to the list 
of parts that must be removed in paragraph (e)(1)(iii) of this AD. ANA 
indicated that first-stage HPT air seals are included in the Table of 
Parts in PW SB No. PW4G-112-72-332. This SB lists parts that must be 
removed from service if a circumferential crack of any length is found 
propagated through the web of the forward flange outer diameter of the 
second-stage HPT air seal.
    We disagree. If a crack is found in the second-stage HPT air seal, 
then the life of mating hardware is adversely affected to the point 
that the mating hardware must be removed. The first-stage HPT air seal 
is not a life-limited part like the mating hardware we require to be 
removed if a crack is found. The first-stage HPT air seal, therefore, 
may be retained unless it is found damaged in the course of removing 
the rest of the mating hardware. We did not change this AD.

Request To Develop Tracking Process for Parts Being Removed From 
Service

    UA requested that this AD consider record-keeping for the results 
of the FPI for second-stage HPT air seals that are being removed from 
service. UA commented that inspecting parts being removed from service 
is not common practice and that the burden of showing compliance to 
this AD rests with the operator and appropriate paper records need to 
be maintained. While the commenter did not request a specific change to 
this AD, we regard the comment as a reference to the lack of a standard 
industry practice for inspecting parts that are being removed from 
service. This refers to the second-stage HPT air seals, P/N 54L041, 
which are subject to an FPI after removal from service.
    We partially agree. We agree that inspecting parts removed from 
service for their impact on other parts is not common practice. 
However, operators must maintain adequate records of the maintenance 
they perform to show that the product has been properly maintained and 
is eligible for return to service as airworthy. We disagree that we 
need to impose additional record keeping requirements on operators to 
ensure that they comply with their obligation to perform maintenance 
properly. It is up to each operator to establish its own record-keeping 
process. We did not change this AD.

Request To Develop Reporting and Tracking Processes for Spare Parts

    UA indicated the need for a procedure for determining the 
serviceability of spare parts, i.e., first-stage HPT hubs, second-stage 
HPT hubs, and second-stage HPT blade retaining plates, that may have 
been mated previously to a cracked second-stage HPT air seal. UA noted 
that the continued serviceability of these spare parts depends on the 
result of the inspection of the second-stage HPT air seal that the 
parts were mated to while in service. UA would like procedures 
established to identify, tag, and mark these spare parts. UA noted that 
such procedures are not standardized within industry. UA also suggested 
that PW SB No. PW4G-112-A72-330 be revised to add some kind of marking 
to notate serviceable spare parts.
    We partially agree. We do not find the need to mandate a procedure 
to track these spare parts. Each operator should establish its own 
process for tracking its spare parts. We did not change this AD.
    We agree, however, that mating hardware previously installed with 
cracked second-stage HPT air seals is not eligible for installation as 
airworthy. We changed this AD to establish an installation prohibition 
to clarify that life-limited parts previously mated to a cracked 
second-stage HPT air seal, P/N 54L041, cannot be reinstalled. We added 
Installation Prohibition paragraph (f)(2) to this AD, which states: 
``After the effective date of this AD, do not install any spare first-
stage HPT hub, second-stage HPT hub, or second-stage HPT blade 
retaining plate that was previously mated in service to a second-stage 
HPT air seal, P/N 54L041, that was found to have a through-crack in the 
front forward fillet radius, into any engine.''

Request To Clarify ECI Requirement

    ANA asked that we clarify the requirement for an on-wing ECI of 
second-stage HPT air seals, P/Ns 50L960 and 50L976. The NPRM (79 FR 
32500, June 5, 2014) proposed an on-wing ECI

[[Page 69371]]

for second-stage HPT air seal, P/N 54L041, only.
    We disagree. We are not requiring an ECI for second-stage HPT air 
seals, P/Ns 50L960 and 50L976, because the ECI probe is not compatible 
with the geometry of those P/Ns. Also, removal of these parts at the 
next piece-part exposure without interim inspections maintains an 
acceptable level of safety. We did not change this AD.

Agreement With This AD

    The Boeing Company expressed support for the NPRM (79 FR 32500, 
June 5, 2014) as proposed.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
this AD with the changes described previously. We also determined that 
these changes will not increase the economic burden on any operator or 
increase the scope of this AD.

Costs of Compliance

    We estimate that this AD affects 116 engines installed on airplanes 
of U.S. registry. We also estimate that it will take about 5 hours to 
perform the inspection required by this AD. The average labor rate is 
$85 per hour. We estimate that two engines will also require removal of 
the first-stage HPT hub, second-stage HPT hub, and second-stage HPT 
blade retaining plate. We estimate that parts will cost about $698,920 
per engine. Based on these figures, we estimate the total cost of this 
AD on U.S. operators to be $23,420,020.

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

    We have determined that 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 to the extent 
that it justifies making a regulatory distinction, 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 removing Airworthiness Directive (AD) 
2013-15-09, Amendment 39-17525 (78 FR 49111, August 13, 2013), and 
adding the following new AD:

2014-23-01 Pratt & Whitney Division: Amendment 39-18017; Docket No. 
FAA-2013-0072; Directorate Identifier 2013-NE-04-AD.

(a) Effective Date

    This AD is effective December 26, 2014.

(b) Affected ADs

    This AD supersedes AD 2013-15-09, Amendment 39-17525 (78 FR 
49111, August 13, 2013).

(c) Applicability

    This AD applies to all Pratt & Whitney Division (PW) PW4074, 
PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 turbofan 
engine models with second-stage high-pressure turbine (HPT) air 
seal, part number (P/N) 54L041, 50L960, or 50L976, installed.

(d) Unsafe Condition

    This AD was prompted by additional reports of cracking in the 
second-stage HPT air seal. We are issuing this AD to prevent failure 
of the second-stage HPT air seal, which could lead to uncontained 
engine failure and damage to the airplane.

(e) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.
    (1) At the next piece-part exposure after the effective date of 
this AD, do the following:
    (i) Remove from service second-stage HPT air seals, P/Ns 50L960, 
50L976, and 54L041.
    (ii) Perform a fluorescent-penetrant inspection (FPI) of the 
second-stage HPT air seal, P/N 54L041, for a through-crack in the 
front forward fillet radius.
    (iii) If a through-crack in the front forward fillet radius is 
found, remove the first-stage HPT hub, second-stage HPT hub, and 
second-stage HPT blade retaining plate from service. Do not 
reinstall the first-stage HPT hub, second-stage HPT hub, or second-
stage HPT blade retaining plate into any engine.
    (2) For engines with second-stage HPT air seals, P/N 54L041, 
installed, perform initial and repetitive inspections for cracks on-
wing until the part is removed from the engine as follows:
    (i) Perform an initial eddy current inspection (ECI) for cracks 
within 1,000 cycles-in-service after September 17, 2013, or before 
further flight, whichever occurs later.
    (ii) Thereafter, repeat the ECI every 1,200 cycles since last 
inspection, or fewer, depending on the results of the inspection.
    (iii) Use section 4.0 of the appendix of PW Alert Service 
Bulletin (ASB) No. PW4G-112-A72-330, Revision 2, dated July 11, 
2013, to perform the inspection and use paragraph 8 of the 
Accomplishment Instructions of PW ASB No. PW4G-112-A72-330, Revision 
2, dated July 11, 2013, to disposition the results of the 
inspection.

(f) Installation Prohibition

    (1) After the effective date of this AD, do not install any 
second-stage HPT air seal, P/N 54L041, P/N 50L960, or P/N 50L976, 
into any engine.
    (2) After the effective date of this AD, do not install any 
spare first-stage HPT hub, second-stage HPT hub, or second-stage HPT 
blade retaining plate that was previously mated in service to a 
second-stage HPT air seal, P/N 54L041, that was found to have a 
through-crack in the front forward fillet radius, into any engine.

(g) Definitions

    For the purpose of this AD:
    (1) Piece-part exposure is when the second-stage HPT air seal is 
removed from the engine and fully disassembled.
    (2) A through-crack is a crack that has propagated through the 
thickness of the part and can be seen on both the inner diameter and 
outer diameter of the front forward fillet radius.

(h) Credit for Previous Actions

    (1) If you performed an ECI of the second-stage HPT air seal 
before the effective date of

[[Page 69372]]

this AD, using PW ASB No. PW4G-112-A72-330, Revision 1, dated 
February 14, 2013, or an earlier version, you have met the 
requirements of paragraph (e)(2)(i) of this AD.
    (2) If you performed an in-shop FPI of the second-stage HPT air 
seal before the effective date of this AD, you have met the 
requirements of paragraph (e)(2)(i) of this AD.

(i) Alternative Methods of Compliance (AMOCs)

    The Manager, Engine Certification Office, FAA, may approve AMOCs 
for this AD. Use the procedures found in 14 CFR 39.19 to make your 
request. You may email your request to: [email protected].

(j) Related Information

    (1) For more information about this AD, contact Jo-Ann 
Theriault, Aerospace Engineer, Engine Certification Office, FAA, 
Engine & Propeller Directorate, 12 New England Executive Park, 
Burlington, MA 01803; phone: 781-238-7105; fax: 781-238-7199; email: 
[email protected].
    (2) PW Service Bulletin (SB) No. PW4G-112-72-332, Revision 3, 
dated June 25, 2014, which is not incorporated by reference in this 
AD, can be obtained from PW, using the contact information in 
paragraph (k)(3) of this AD. This SB provides guidance on how to 
replace the second-stage HPT air seal with an air seal that is more 
resistant to low cycle fatigue cracks.

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (3) The following service information was approved for IBR on 
September 17, 2013 (78 FR 49111, August 13, 2013).
    (i) Pratt & Whitney (PW) Alert Service Bulletin No. PW4G-112-
A72-330, Revision 2, dated July 11, 2013.
    (ii) Reserved.
    (4) For PW service information identified in this AD, contact 
Pratt & Whitney Division, 400 Main St., East Hartford, CT 06108; 
phone: 860-565-8770; fax: 860-565-4503.
    (5) You may view this service information at 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.
    (6) You may view this service information 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 October 30, 2014.
Colleen M. D'Alessandro,
Assistant Directorate Manager, Engine & Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2014-27354 Filed 11-20-14; 8:45 am]
BILLING CODE 4910-13-P

The complete text was extracted from the official GovInfo HTML edition for this publication. Acquired 2026-10-09T02:36:35.172436+00:00. Text extraction preserves the recorded source wording; it does not determine current requirements.

Open the captured official edition

Source SHA-256

81eb01a76f9a31b40313419b824a8a000838e147907eb9ea9bb2c7a3524daa92

Text SHA-256

36cdb4fe7293b40d6739c4fe86a34bca13dea314cfa0699b23ee94101d1d760d