DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA-2013-0072; Directorate Identifier 2013-NE-04-AD] 

RIN 2120-AA64 

Airworthiness Directives; Pratt & Whitney Division Turbofan Engines 

AGENCY: Federal Aviation Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking (NPRM). 

[4910-13-P] 

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

Whitney Division (PW) turbofan engine models PW4074, PW4074D, PW4077, 

PW4077D, PW4084D, PW4090, and PW4090-3 with a certain 2"d-stage high-pressure 

turbine (HPT) air seal part number (PIN) installed. This proposed AD was prompted by 

discovery of cracks in the 2nd -stage HPT air seals. This proposed AD would require, for 

those air seals that meet certain cycles since new (CSN) criteria, inspection and removal 

from service of HPT air seals that fail inspection. We are proposing this AD to prevent 

failure of the 2nd -stage HPT air seal, which could lead to an uncontained engine failure 

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 ofthe following methods: 

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

instructions for submitting comments. 

• 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 AD, contact Pratt & Whitney, 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 ofthis 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 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: Ian Dargin, Aerospace Engineer, 

Engine & Propeller Directorate, FAA, 12 New England Executive Park, Burlington, MA 

01803; phone: 781-238-7178; fax: 781-238-7199; email: ian.dargin@faa.gov. 

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-2013-0072; Directorate Identifier 2013-NE-04-AD" at the 

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

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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.regul ations.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 turbofan engine models PW4074, 

PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 with 2nd-stage 

HPT air seal, PIN 54L041 , installed. This proposed AD was prompted by cracks in 2nd_ 

stage HPT air seals discovered during fluorescent-penetrant inspection (FPI). This 

proposed AD would require, for HPT air seals that meet certain CSN criteria, either onwing eddy current inspection (ECI) or in-shop FPI, and removal from service of any HPT 

air seal that fails inspection. We are proposing this AD to prevent failure of the 2nd -stage 

HPT air seal. This condition, if not corrected, could lead to an uncontained engine failure, 

and damage to the airplane. 

Relevant Service Information 

We reviewed PW Alert Service Bulletin (ASB) PW4G-112-A72-330, Revision 1, 

dated February 26, 2013. The ASB describes procedures for inspecting the integrity of 

2nd -stage HPT air seals and criteria for their removal from service and replacement. 

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. 

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Proposed AD Requirements 

This proposed AD would require accomplishing the actions specified in the 

service information described previously. 

Interim Action 

We consider this proposed AD interim action. PW has not determined the root 

cause of the cracks discovered in 2nd -stage HPT air seals. 

Costs of Compliance 

We estimate that this AD will affect 83 engines installed on airplanes of U.S. 

registry. We also estimate that it would take about 5 hours to perform the inspection 

required by this proposed AD. The costs of an ECI and an FPI are assumed to be equal. 

The average labor rate is $85 per hour. Based on these figures, we estimate the total cost 

of the AD to U.S. operators will be $35,275. 

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 ofthe 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. 

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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, 

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 

I. 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): 

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Pratt & Whitney Division: Docket No. FAA-2013-0072; Directorate Identifier 2013-

NE-04-AD. 

(a) Comments Due Date 

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

PUBLICATION IN THE Federal Register]. 

(b) Affected ADs 

None 

(c) Applicability 

This AD applies to all Pratt & Whitney Division (PW) turbofan engine models 

PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 with 2nd_ 

stage high-pressure turbine (HPT) air seal, part number 54L041 , installed. 

(d) Unsafe Condition 

This AD was prompted by discovery of cracks in the 2nd -stage HPT air seals. We 

are issuing this AD to prevent failure of the 2nd -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) For 2nd -stage HPT air seals that have 1 ,200 or fewer cycles since new ( CSN) 

on the effective date of this AD, perform an on-wing eddy current inspection (ECI) or inshop fluorescent-penetrant inspection (FPI) for cracks within 2,200 CSN. 

(2) For 2nd-stage HPT air seals that have more than 1,200 CSN on the effective 

date of this AD, perform an on-wing ECI or in-shop FPI for cracks within 1,000 cycles 

after the effective date of this AD. 

(3) Thereafter, reinspect with either an on-wing ECI or in-shop FPI every 1,200 

cycles since last inspection. 

( 4) If you find a crack, remove the air seal from service before further flight. 

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(5) Use paragraph 7 ofthe Accomplishment Instructions ofPW Alert Service 

Bulletin (ASB) PW4G-l12-A72-330, Revision 1, dated February 26, 2013, to do the onwing ECI, except the reporting requirement of that step. 

(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 3 9.19 to make your request. 

(g) Related Information 

(1) For more information about this AD, contact Ian Dargin, Aerospace Engineer, 

Engine & Propeller Directorate, FAA, 12 New England Executive Park, Burlington, MA 

01803 ; phone: 781-238-7178; fax: 781-238-7199; email: ian.dargin@,faa.gov . 

(2) Refer to PW ASB PW4G-112-A72-330, Revision 1, dated February 26, 2013, 

for related information. 

(3) For service information identified in this AD, contact Pratt & Whitney, 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. 

Issued in Burlington, Massachusetts, on March 4, 2013. 

w~ ~~~ f)rJi2udcwJ_;j) 

Colleen M. D' Alessandro, 

Assistant Manager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

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