Document ID: FAA-2010-1095-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Pratt and Whitney (PW) Models PW4074 and PW4077 Turbofan Engines
Posted Date: 2010-11-02T04:00Z

[Federal Register: November 2, 2010 (Volume 75, Number 211)]
[Proposed Rules]               
[Page 67253-67254]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr02no10-11]                         

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Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

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[[Page 67253]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-1095; Directorate Identifier 2009-NE-40-AD]
RIN 2120-AA64

 
Airworthiness Directives; Pratt & Whitney (PW) Models PW4074 and 
PW4077 Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for PW PW4074 and PW4077 turbofan engines with 15th stage high-pressure 
compressor (HPC) disks, part number (P/N) 55H615, installed. This 
proposed AD would require 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 proposed AD results from multiple shop findings of 
cracked 15th stage HPC disks. We are proposing this AD to prevent 
cracks from propagating into the bolt hole, which could result in a 
failure of the 15th stage HPC disk, uncontained engine failure, and 
damage to the airplane.

DATES: We must receive any comments on this proposed AD by January 3, 
2011.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     Federal eRulemaking Portal: Go to http://
www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 1200 New Jersey Avenue, SE., West Building Ground 
Floor, Room W12-140, Washington, DC 20590-0001.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
     Fax: (202) 493-2251.
    Contact Pratt & Whitney, 400 Main St., East Hartford, CT 06108; 
telephone (860) 565-7700; fax (860) 565-1605, for a copy of the service 
information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT: James Gray, Aerospace Engineer, Engine 
Certification Office, FAA, Engine & Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
james.e.gray@faa.gov; telephone (781) 238-7742; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send us any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2010-1095; Directorate 
Identifier 2009-NE-40-AD'' in the subject line of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of the proposed AD. We will consider 
all comments received by the closing date and may amend the proposed AD 
in light of those comments.
    We will post all comments we receive, without change, to http://
www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact 
with FAA personnel concerning this proposed AD. Using the search 
function of the Web site, anyone can find and read the comments in any 
of our dockets, including, if provided, the name of the individual who 
sent the comment (or signed the comment on behalf of an association, 
business, labor union, etc.). You may review the DOT's complete Privacy 
Act Statement in the Federal Register published on April 11, 2000 (65 
FR 19477-78).

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Operations office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Operations office (telephone (800) 647-5527) is 
the same as the Mail address provided in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.

Discussion

    We have received reports of multiple shop findings of cracked 15th 
stage HPC disks that required removing the disks from service. As of 
June 30, 2010, 53 disks with cracks in the front rail of the load and 
lock slots have been reported. Engineering investigation determined 
that the initiation was the result of thermal mechanical fatigue. Three 
of the disks had cracks that propagated radially into the bolt holes. 
These cracks could propagate further and lead to failure of the disk.
    This condition, if not corrected, could result in a failure of the 
15th stage HPC disk, uncontained engine failure, and damage to the 
airplane.

Relevant Service Information

    We have reviewed and approved the technical contents of PW Service 
Bulletin (SB) PW4G-112-72-309, Revision 1, dated July 1, 2010, that 
describes procedures for performing a BSI or ECI for cracks in the 
front rail of the outer rim of the 15th stage HPC disk.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. We are proposing this AD, which would 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. The 
proposed AD would require you to use the service information described 
previously to perform these actions.

Interim Action

    These actions are interim actions and we may take further 
rulemaking actions in the future.

Costs of Compliance

    We estimate that this proposed AD would affect 44 engines installed 
on airplanes of U.S. registry. Prorated parts

[[Page 67254]]

would cost about $66,000 per 15th stage HPC disk. Based on these 
figures, we estimate the total cost of the proposed 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

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 the proposed AD:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979); and
    3. Would not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Under the authority delegated to me by the Administrator, the 
Federal Aviation Administration proposes to amend 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. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive:

Pratt & Whitney: Docket No. FAA-2010-1095; Directorate Identifier 
2009-NE-40-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by January 3, 
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. These engines are 
installed on, but not limited to, Boeing 777-200 series and 777-300 
series airplanes.

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, perform a borescope inspection (BSI) or eddy 
current inspection (ECI):
    (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 cycles-in-service (CIS) after the effective date 
of this AD, whichever is latest.
    (3) If you see a suspected crack using a BSI from paragraph 
(g)(2) of this AD, but can't visually confirm a crack, perform an 
ECI within 5 CIS after the BSI.
    (4) If you find a crack using any inspection, 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) Contact James Gray, Aerospace Engineer, Engine Certification 
Office, FAA, Engine & Propeller Directorate, 12 New England 
Executive Park, Burlington, MA 01803; e-mail: james.e.gray@faa.gov; 
telephone (781) 238-7742; fax (781) 238-7199, for more information 
about this AD.
    (k) Pratt & Whitney Service Bulletin PW4G-112-72-309 Revision 1, 
dated July 1, 2010, pertains to the subject of this AD. Contact 
Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone 
(860) 565-7700; fax (860) 565-1605, for a copy of this service 
information.

    Issued in Burlington, Massachusetts, on October 26, 2010.
Karen M. Grant,
Acting Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2010-27607 Filed 11-1-10; 8:45 am]
BILLING CODE 4910-13-P