[4910-13-P]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-0787; Directorate Identifier 2015-NE-10-AD]

RIN 2120-AA64

Airworthiness Directives; Pratt & Whitney Division Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: We propose to adopt a new airworthiness directive (AD) for all Pratt & 

Whitney Division (PW) PW4164, PW4168, PW4168A, PW4164C, PW4164C/B, 

PW4164-1D, PW4168-1D, PW4168A-1D, PW4170, PW4164C-1D, PW4164C/B-1D,

PW4050, PW4052, PW4056, PW4060, PW4060A, PW4060C, PW4062, PW4062A, 

PW4152, PW4156, PW4156A, PW4158, PW4160, PW4460, PW4462, and PW4650 

turbofan engines with a low-pressure turbine (LPT) 4th stage inner air seal (IAS), P/N 

51N038, installed. This proposed AD was prompted by the discovery, during routine 

overhaul of the LPT, of cracks in the barrel section of the 4

th stage IAS. This proposed 

AD would require removal of the LPT 4th stage IAS, P/N 51N038, according to a 

prescribed schedule. We are proposing this AD to prevent failure of the LPT 4th stage 

IAS, which could lead to an uncontained IAS release, damage to the engine, and damage 

to the airplane.

DATES: We must receive comments on this proposed AD by [INSERT DATE 60

DAYS AFTER DATE OF PUBLICATION IN THE Federal Register].

ADDRESSES: You may send comments, using the procedures found in 14 CFR 11.43 

and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the 

instructions for submitting comments.
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• Fax: 202-493-2251.

• Mail: U.S. Department of Transportation, Docket Operations, M-30, West 

Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 

20590.

• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., 

Monday through Friday, except Federal holidays.

For service information identified in this proposed 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- 2015-0787; 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 proposed AD, the regulatory evaluation, any

comments received, and other information. The street address for the Docket Office 

(phone: 800-647-5527) is in the ADDRESSES section. Comments will be available in the 

AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Katheryn Malatek, Aerospace 

Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New 

England Executive Park, Burlington, MA 01803; phone: 781-238-7747; fax: 781-238-

7199; email: katheryn.malatek@faa.gov.
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SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this 

proposal. Send your comments to an address listed under the ADDRESSES section. 

Include “Docket No. FAA- 2015-0787; Directorate Identifier 2015-NE-10-AD” at the

beginning of your comments. We specifically invite comments on the overall regulatory, 

economic, environmental, and energy aspects of this proposed AD. We will consider all 

comments received by the closing date and may amend this proposed AD because 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 we receive about this 

proposed AD.

Discussion

We propose to adopt a new AD for all PW PW4164, PW4168, PW4168A, 

PW4164C, PW4164C/B, PW4164-1D, PW4168-1D, PW4168A-1D, PW4170, 

PW4164C-1D, PW4164C/B-1D, PW4050, PW4052, PW4056, PW4060, PW4060A, 

PW4060C, PW4062, PW4062A, PW4152, PW4156, PW4156A, PW4158, PW4160, 

PW4460, PW4462, and PW4650 turbofan engines with an LPT 4

th IAS, P/N 51N038, 

installed. This proposed AD was prompted by 9 occasions of discovering, during routine 

overhaul of the LPT, cracks in the barrel section of the 4

th stage IAS. This condition, if 

not corrected, could result in uncontained IAS release, damage to the engine, and damage 

to the aircraft. This proposed AD would require removal of the 4

th stage IAS, P/N 

51N038, according to a prescribed schedule. We are proposing this AD to prevent failure 

of the LPT 4th stage IAS, which could lead to an uncontained IAS release, damage to the 

engine, and damage to the airplane.
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Related Service Information

We reviewed PW Alert Service Bulletin (ASB) No. PW4G-100-A72-254, dated 

December 12, 2014. The ASB describes procedures and timetables for removing the LPT 

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th stage IAS. This service information is reasonably available; see ADDRESSES for 

ways to access this service information.

FAA’s Determination

We are proposing this AD because we evaluated all the relevant information and 

determined the unsafe condition described previously is likely to exist or develop in other 

products of the same type design.

Proposed AD Requirements

This proposed AD would require removal of the LPT 4th stage IAS, P/N 51N038, 

according to a prescribed schedule.

Differences Between this Proposed AD and the Service Information

PW ASB No. PW4G-100-A72-254, dated December 12, 2014, applies to certain 

PW4000 engine models. This proposed AD applies to the 7 engine models listed in the 

ASB, plus 4 additional PW4000 engine models certificated for use in the U.S. for which 

the affected LPT 4th IAS, P/N 51N038, is eligible for installation. These 11 engine

models are listed in paragraph (c)(1) of this AD. 

We further expanded the applicability to cover 16 additional engine models, listed 

in paragraph (c)(2) of this AD, which are prohibited from installing P/N 51N038, if that 

part was ever installed on any engine listed in paragraph (c)(1) of this AD. The unsafe 

condition described in paragraph (d) of this AD could exist in the part if it was ever 

operated in any engine listed in paragraph (c)(1) of this AD. 

Costs of Compliance

We estimate that this proposed AD affects 72 engines installed on airplanes of 

U.S. registry. We also estimate that 9 of the engines would require replacement parts 
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during shop visit, and that for these engines the pro-rated replacement parts cost would be 

$23,805 per engine, and compliance with this proposed AD would require about 49 hours 

of labor per engine. The average labor rate is $85 per hour. We also estimate that 63 of 

the engines would require replacement parts during LPT overhaul, that the prorated 

replacement parts cost for these 63 engines would be $43,545 per engine, and that 

compliance with this proposed AD for these 63 engines would require 0 additional hours 

of labor per engine since the parts are already exposed during LPT overhaul. Based on 

these figures, we estimate the cost of this proposed AD on U.S. operators to be 

$2,995,065.

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 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, 
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or on the distribution of power and responsibilities among the various levels of 

government.

For the reasons discussed above, I certify this proposed regulation:

(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),

(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.

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA 

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.

§ 39.13 [Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive 

(AD):

Pratt & Whitney Division: Docket No. FAA- 2015-0787; Directorate Identifier 2015-

NE-10-AD.

(a) Comments Due Date

We must receive comments by [INSERT DATE 60 DAYS AFTER DATE OF 

PUBLICATION IN THE Federal Register].
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(b) Affected ADs

None.

(c) Applicability

This AD applies to:

(1) All Pratt & Whitney Division (PW) PW4164, PW4168, PW4168A, 

PW4164C, PW4164C/B, PW4164-1D, PW4168-1D, PW4168A-1D, PW4170, 

PW4164C-1D, and PW4164C/B-1D turbofan engines with a low-pressure turbine (LPT) 

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th stage inner air seal (IAS), part number (P/N) 51N038, installed.

(2) All PW4050, PW4052, PW4056, PW4060, PW4060A, PW4060C, PW4062, 

PW4062A, PW4152, PW4156, PW4156A, PW4158, PW4160, PW4460, PW4462, and 

PW4650 turbofan engines with an LPT 4

th stage IAS, P/N 51N038, installed.

(d) Unsafe Condition

This AD was prompted by the discovery, during routine overhaul of the LPT, of 

cracks in the barrel section of the 4

th stage IAS which could, if not corrected, result in 

uncontained IAS release, damage to the engine, and damage to the aircraft. We are 

issuing this AD to prevent failure of the LPT 4th stage IAS, which could lead to an 

uncontained IAS release, damage to the engine, and damage to the airplane.

(e) Compliance

Comply with this AD within the compliance times specified, unless already done.

For the engines listed in paragraph (c)(1) of this AD:

(1) At each LPT overhaul after the effective date of this AD remove from service

the LPT 4th stage IAS, P/N 51N038.

(2) At each engine shop visit after the effective date of this AD, remove from 

service the LPT 4

th stage IAS, P/N 51N038, if it has more than 10,900 cycles since new.
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(f) Installation prohibition

(1) Do not install any LPT 4th stage IAS, P/N 51N038, with more than 0 flight 

cycles on any engine listed in paragraph (c)(1) of this AD.

(2) Do not install on any engine listed in paragraphs (c)(2) of this AD, any LPT 

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th stage IAS, P/N 51N038, which was previously installed on any engine listed in 

paragraph (c)(1) of this AD. 

(g) Definitions

For the purposes of this AD: 

(1) An LPT overhaul is defined as maintenance which involves disassembly of the 

LPT rotor module.

(2) An “engine shop visit” is the induction of an engine into the shop for 

maintenance involving the separation of pairs of major mating engine flanges (lettered 

flanges). The separation of engine flanges solely for the purpose of transportation without 

subsequent engine maintenance does not constitute an engine shop visit.

(h) 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.

(i) Related Information

(1) For more information about this AD, contact Katheryn Malatek, Aerospace 

Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New 

England Executive Park, Burlington, MA 01803; phone: 781-238-7747; fax: 781-238-

7199; email: katheryn.malatek@faa.gov.

(2) PW Alert Service Bulletin No. PW4G-100-A72-254, dated December 12, 

2014, can be obtained from PW using the contact information in paragraph (i)(3) of this 

AD.
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(3) 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. 

(4) 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.

Issued in Burlington, Massachusetts, on May 13, 2015.

Colleen M. D’Alessandro,

Assistant Directorate Manager, Engine & Propeller Directorate,

Aircraft Certification Service.