
[Federal Register Volume 76, Number 150 (Thursday, August 4, 2011)]
[Rules and Regulations]
[Pages 47056-47057]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-19476]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-1095; Directorate Identifier 2009-NE-40-AD; 
Amendment 39-16742; AD 2011-14-07]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney (PW) Models PW4074 and 
PW4077 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 the 
products listed above. This AD requires removing the 15th stage HPC 
disk within 12,000 cycles since new (CSN) or, for any disks that exceed 
12,000 CSN after the effective date of this AD using a drawdown plan 
that includes a borescope inspection (BSI) or eddy current inspection 
(ECI) of the rim for cracks. This AD was prompted by multiple shop 
findings of cracked 15th stage HPC disks. We are issuing this AD to 
prevent cracks from propagating into the disk bolt holes, which could 
result in a failure of the 15th stage HPC disk, uncontained engine 
failure, and damage to the airplane.

DATES: This AD is effective September 8, 2011.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of September 8, 
2011.

ADDRESSES: For service information identified in this AD, contact Pratt 
& Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 565-
7700; fax (860) 565-1605. You may review copies of the referenced 
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: Ian Dargin, Aerospace Engineer, Engine 
Certification Office, FAA, 12 New England Executive Park, Burlington, 
MA 01803; phone: (781) 238-7178; fax: (781) 238-7199; e-mail: 
ian.dargin@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an airworthiness directive (AD) that would apply to 
the specified products. That NPRM published in the Federal Register on 
November 2, 2010, (75 FR 67253). That NPRM proposed to require removing 
the 15th stage HPC disk before 12,000 CSN, or for any disks that exceed 
12,000 CSN after the effective date of this AD, using a drawdown plan 
that includes a BSI or ECI of the rim for cracks.

Comments

    We gave the public the opportunity to participate in developing 
this AD. We received no comments on the NPRM or

[[Page 47057]]

on the determination of the cost to the public.

Conclusion

    We reviewed the relevant data and determined that air safety and 
the public interest require adopting the AD as proposed.

Costs of Compliance

    We estimate that this AD will affect 44 engines installed on 
airplanes of U.S. registry. Prorated parts life will cost about $66,000 
per 15th stage HPC disk. Based on these figures, we estimate the total 
cost of the AD to U.S. operators to be $2,904,000.

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):

2011-14-07 Pratt & Whitney: Amendment 39-16742; Docket No. FAA-2010-
1095; Directorate Identifier 2009-NE-40-AD.

Effective Date

    (a) This AD is effective September 8, 2011.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Pratt & Whitney (PW) PW4074 and PW4077 
turbofan engines with 15th stage high-pressure compressor (HPC) 
disks, part number (P/N) 55H615, installed.

Unsafe Condition

    (d) This AD results from multiple shop findings of cracked 15th 
stage HPC disks. We are issuing this AD to prevent cracks from 
propagating into the bolt holes of the 15th stage HPC disk, which 
could result in a failure of the 15th stage HPC disk, uncontained 
engine failure, and damage to the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified unless the 
actions have already been done.
    (f) For 15th stage HPC disks that have 9,865 or fewer cycles 
since new (CSN) on the effective date of this AD, remove the disk 
from service before accumulating 12,000 CSN.
    (g) For 15th stage HPC disks that have accumulated more than 
9,865 CSN on the effective date of this AD, do the following:
    (1) Remove the disk from service at the next piece-part exposure 
above 12,000 CSN, not to exceed 2,135 cycles-in-service (CIS) after 
the effective date of this AD.
    (2) For 15th stage HPC disks that are installed in the engine 
and exceed 12,000 CSN on the effective date of this AD, perform a 
borescope inspection (BSI) or eddy current inspection (ECI) of the 
disk rim according to the following schedule:
    (i) Within 2,400 cycles-since-last fluorescent penetrant 
inspection or ECI, or
    (ii) Within 1,200 cycles-since-last BSI, or
    (iii) Within 55 CIS after the effective date of this AD, 
whichever occurs later.
    (3) If the BSI from paragraph (g)(2) of this AD indicates the 
presence of a crack in the disk rim, but you can't visually confirm 
a crack, perform an ECI within 5 CIS after the BSI.
    (4) If you confirm a crack in the disk rim using any inspection 
method, remove the disk from service before further flight.
    (h) Use paragraph 1.A. or 1.B. of the Accomplishment 
Instructions ``For Engines Installed on the Aircraft'' or 1.A. or 
1.B. of the Accomplishment Instructions ``For Engines Removed from 
the Aircraft,'' of PW Service Bulletin PW4G-112-72-309, Revision 1, 
dated July 1, 2010 to perform the inspections.

Alternative Methods of Compliance

    (i) The Manager, Engine Certification Office, has the authority 
to approve alternative methods of compliance for this AD if 
requested using the procedures found in 14 CFR 39.19.

Related Information

    (j) For more information about this AD, contact Ian Dargin, 
Aerospace Engineer, Engine Certification Office, FAA, 12 New England 
Executive Park, Burlington, MA 01803; phone: (781) 238-7178; fax: 
(781) 238-7199; e-mail: ian.dargin@faa.gov.

Material Incorporated by Reference

    (k) You must use Pratt & Whitney Service Bulletin PW4G-112-72-
309, Revision 1, dated July 1, 2010, to do the actions required by 
this AD, unless the AD specifies otherwise.
    (1) The Director of the Federal Register approved the 
incorporation by reference of the service information contained in 
this AD under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) For service information identified in this AD, contact Pratt 
& Whitney, 400 Main St., East Hartford, CT 06108; telephone (860) 
565-7700; fax (860) 565-1605.
    (3) You may review copies of the 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.
    (4) You may also review copies of 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 an NARA facility, call 202-741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Burlington, Massachusetts, on June 24, 2011.
Peter A. White,
Acting Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-19476 Filed 8-3-11; 8:45 am]
BILLING CODE 4910-13-P


