
[Federal Register Volume 81, Number 81 (Wednesday, April 27, 2016)]
[Rules and Regulations]
[Pages 24696-24699]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-09687]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-4474; Directorate Identifier 2015-NE-34-AD; 
Amendment 39-18485; AD 2016-08-09]
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 certain

[[Page 24697]]

Pratt & Whitney Division (PW) PW4000-94 inch and PW4000-100 inch model 
turbofan engines. This AD was prompted by a report of a crack found in 
the high-pressure compressor (HPC) 10th stage disk. This AD requires 
performing an ultrasonic inspection (USI) or an eddy current inspection 
(ECI) of the HPC 10th stage disk. We are issuing this AD to prevent 
failure of the HPC 10th stage disk, uncontained disk release, damage to 
the engine, and damage to the airplane.

DATES: This AD is effective June 1, 2016.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of June 1, 2016.

ADDRESSES: For service information identified in this final rule, 
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, 1200 
District Avenue, Burlington, MA. For information on the availability of 
this material at the FAA, call (781) 238-7125. It is also available on 
the Internet at http://www.regulations.gov by searching for and 
locating Docket No. FAA-2015-4474.

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-2015-
4474; 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: Katheryn Malatek, Aerospace Engineer, 
Engine Certification Office, FAA, Engine & Propeller Directorate, 1200 
District Avenue, Burlington, MA 01803; phone: 781-238-7747; fax: 781-
238-7199; email: katheryn.malatek@faa.gov.

SUPPLEMENTARY INFORMATION: 

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 by adding an AD that would apply to certain PW PW4000-94 inch 
turbofan engines with HPC 10th stage disk, part number (P/N) 51H710 or 
53H976-06, installed and certain PW4000-100 inch turbofan engines with 
HPC 10th stage disk, P/N 53H976-06, installed. The NPRM published in 
the Federal Register on December 9, 2015 (80 FR 76400). The NPRM was 
prompted by a report of a crack found in the HPC 10th stage disk. The 
root cause of the crack was a manual polishing procedure, previously 
used during manufacture, that caused surface scratches on the disk. The 
NPRM proposed to require a USI or ECI of the HPC 10th stage disk. We 
are issuing this AD to prevent failure of the HPC 10th stage disk, 
which could lead to an uncontained disk release, damage to the engine, 
and damage to the airplane.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the NPRM (80 
FR 76400, December 9, 2015) and the FAA's response to each comment.

Support for the NPRM

    The Boeing Company and United Airlines expressed support for the 
NPRM (80 FR 76400, December 9, 2015).

Request To Use ECI as Follow-on to USI

    American Airlines requested that we revise Compliance paragraph (e) 
of this AD to add a statement that the ECI can be used to confirm the 
presence of a crack if a USI is initially performed and the ECI is the 
final authority on whether or not a crack is present on the disk.
    We agree. We revised Compliance paragraph (e) of this AD to allow a 
follow-on ECI.

Request To Allow Disk Replacement Repairs

    Atlas Air requested that we revise the Compliance paragraph (e) of 
this AD to allow use of disk replacement repairs per the PW PW4000-94/
100 Clean, Inspect, Repair (CIR) Manual Part No. 51A357, Section 72-35-
10, Repair 07.
    We disagree. This AD requires removal of the 10th stage disk if it 
fails inspection. There are no FAA-approved repairs allowed on the 10th 
stage disk. The previously approved PW4000-94/100 CIR Manual Part No. 
51A357, Section 72-35-07, Repair 04 to the drum rotor, replaces the 
disk, resulting in a part eligible for installation. We did not change 
this AD.

Request To Allow ECI at Overhaul

    Air India Limited requested that Compliance paragraph (e) of this 
AD allow an ECI when the HPC is ``overhauled'' rather than when it is 
``removed from the engine.'' Air India Limited indicated that 
``overhauled'' is clearer than ``removed from the engine''.
    We disagree. The intent of this AD is to inspect the 10th stage 
disk at exposure. The phrase, ``Whenever the HPC front drum rotor is 
removed from the engine . . .'' clearly describes the appropriate level 
of exposure for performing the ECI. We did not change this AD.

Request To Waive Repeat USI

    Air India Limited requested that we revise Compliance paragraph (e) 
of this AD to indicate that a repeat USI should be waived to reduce the 
maintenance burden if the low-pressure turbine (LPT) is removed in less 
than 100 hours since the last USI.
    We disagree. Our safety risk assessment assumed that a USI is 
performed whenever the high-pressure turbine (HPT) or LPT is removed 
from the engine and an ECI is performed whenever the HPC front drum 
rotor disk assembly is removed from the engine. We determined the 
inspection interval in the Compliance paragraph (e) of this AD provides 
an acceptable level of safety. We did not change this AD.

Request To Remove Compliance Statement

    FedEx requested that we revise Compliance paragraph (e) of this AD 
to remove the statement, ``Comply with this AD within the compliance 
times specified, unless already done.'' FedEx stated that there are no 
compliance times specified and the compliance requires a repetitive 
inspection, so the statement does not apply.
    We disagree. The statement ``. . . unless already done'' allows an 
operator who has performed an initial inspection before the effective 
date of the AD, but has not yet returned the part to service, to take 
credit for that action. While there is no calendar or cyclic time 
given, the requirements of this AD must be met when the HPT, LPT, or 
HPC front drum rotor disk assembly is removed from the engine. We did 
not change this AD.

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 have determined that 
these minor changes:
     [Agr]re consistent with the intent that was proposed in 
the NPRM (80 FR 76400, December 9, 2015) for correcting the unsafe 
condition; and
     Do not add any additional burden upon the public than was 
already

[[Page 24698]]

proposed in the NPRM (80 FR 76400, December 9, 2015).
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this AD.

Related Service Information Under 1 CFR Part 51

    We reviewed PW Alert Service Bulletin (ASB) PW4G-100-A72-255, dated 
August 31, 2015 and PW ASB PW4ENG A72-833, dated August 20, 2015. The 
ASBs provide lists of affected HPC disks and describe procedures for 
USI and ECI of the HPC 10th stage disk. This service information is 
reasonably available because the interested parties have access to it 
through their normal course of business or by the means identified in 
the ADDRESSES section.

Costs of Compliance

    We estimate that this AD affects 763 engines installed on airplanes 
of U.S. registry. We also estimate that it would take about 12 hours 
per engine to do the inspection. The average labor rate is $85 per 
hour. Based on these figures, we estimate the cost of this AD on U.S. 
operators to be $778,260.

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 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 adding the following new airworthiness 
directive (AD):

2016-08-09 Pratt & Whitney Division: Amendment 39-18485; FAA-2015-
4474; Directorate Identifier 2015-NE-34-AD.

(a) Effective Date

    This AD is effective June 1, 2016.

(b) Affected ADs

    None.

(c) Applicability

    (1) This AD applies to all Pratt & Whitney Division (PW) PW4050, 
PW4052, PW4056, PW4060, PW4060A, PW4060C, PW4062, PW4062A, PW4152, 
PW4156, PW4156A, PW4158, PW4160, PW4460, PW4462, and PW4650 turbofan 
engines, including models with a ``-3'' suffix, with one of the 
following installed:
    (i) High-pressure compressor (HPC) 10th stage disk, part number 
(P/N) 51H710, with a serial number (S/N) listed in Table 1 of PW 
Alert Service Bulletin (ASB) PW4ENG A72-833, dated August 20, 2015; 
or
    (ii) HPC 10th stage disk, P/N 53H976-06, with an S/N listed in 
Table 2 of PW ASB PW4ENG A72-833, dated August 20, 2015.
    (2) This AD also applies to all PW PW4164, PW4168, PW4168A, 
PW4164C, PW4164C/B, PW4170, PW4168A-1D, PW4168-1D, PW4164-1D, 
PW4164C-1D, and PW4164C/B-1D turbofan engines with an HPC 10th stage 
disk, P/N 53H976-06, with an S/N listed Table 1 of PW ASB PW4G-100-
A72-255, dated August 31, 2015, installed.

(d) Unsafe Condition

    This AD was prompted by a report of a crack found in the HPC 
10th stage disk. We are issuing this AD to prevent failure of the 
HPC 10th stage disk, uncontained disk release, damage to the engine, 
and damage to the airplane.

(e) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.
    (1) After the effective date of this AD, whenever the high-
pressure turbine (HPT) or low-pressure turbine (LPT) is removed from 
the engine, perform an ultrasonic inspection (USI) of the HPC 10th 
stage disk for cracks. If the HPC 10th stage disk fails the USI, 
perform a follow-on eddy current inspection (ECI) or remove the disk 
from service and replace with a part eligible for installation.
    (2) After the effective date of this AD, whenever the HPC front 
drum rotor disk assembly is removed from the engine, perform an ECI 
of the HPC 10th stage disk for cracks. Remove from service any HPC 
10th stage disk that fails inspection and replace with a part 
eligible for installation. A USI as required by paragraph (e)(1) of 
this AD is not required if an ECI is performed.

(f) 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: ANE-AD-AMOC@faa.gov.

(g) Related Information

    For more information about this AD, contact Katheryn Malatek, 
Aerospace Engineer, Engine Certification Office, FAA, Engine & 
Propeller Directorate, 1200 District Avenue, Burlington, MA 01803; 
phone: 781-238-7747; fax: 781-238-7199; email: 
katheryn.malatek@faa.gov.

(h) 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.
    (i) Pratt & Whitney (PW) Alert Service Bulletin (ASB) PW4G-100-
A72-255, dated August 31, 2015.
    (ii) PW ASB PW4ENG A72-833, dated August 20, 2015.
    (3) 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.
    (4) You may view this service information at FAA, Engine & 
Propeller Directorate, 1200 District Avenue, Burlington, MA. For 
information on the availability of this material at the FAA, call 
781-238-7125.
    (5) You may view this 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

[[Page 24699]]

202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Burlington, Massachusetts, on April 7, 2016.
Colleen M. D'Alessandro,
Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-09687 Filed 4-26-16; 8:45 am]
 BILLING CODE 4910-13-P


