[4910-13-P]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-0266; Directorate Identifier 2015-NE-03-AD; Amendment 

39-18185; AD 2015-12-10]

RIN 2120-AA64

Airworthiness Directives; Pratt & Whitney Division Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

SUMMARY: We are adopting a new airworthiness directive (AD) for all Pratt & 

Whitney Division (PW) PW6122A and PW6124A turbofan engines. This AD requires 

initial and repetitive borescope inspections (BSIs) of the high-pressure compressor (HPC) 

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th stage integrally bladed (IB) rotor aft integral arm for cracks until replacement of the 

HPC 7

th stage IB rotor using non-silver-plated nuts. This AD was prompted by reports of

crack finds in the HPC 7

th stage IB rotor. We are issuing this AD to prevent HPC 7th

stage IB rotor fractures, which could lead to uncontained engine failure and damage to 

the airplane.

DATES: This AD is effective [INSERT DATE 15 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER].

The Director of the Federal Register approved the incorporation by reference of 

certain publications listed in this AD as of [INSERT DATE 15 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER].

We must receive comments on this AD by [INSERT DATE 45 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:
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• Federal eRulemaking Portal: Go to http://www.regulations.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: U.S. Department of Transportation, Docket Operations, M-30, 

West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., 

Washington, DC 20590, 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 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-2015-0266.

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-2015-0266; 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 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: Wego Wang, Aerospace Engineer, 

Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England 
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Executive Park, Burlington, MA 01803; phone: 781-238-7134; fax: 781-238-7199; email: 

wego.wang@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

We received reports of cracks in the PW6122A and the PW6124A HPC 7

th stage

IB rotor aft integral arm. The root cause is the presence of silver-plated nuts reacting with 

hot titanium in a high sulfur/high chlorine environment. This AD requires initial and 

repetitive BSIs of the HPC 7

th stage IB rotor. This AD also requires, as terminating 

action, replacement of the HPC 7th stage IB rotor and HPC 7th stage IB rotor silver-plated 

nuts with non-silver-plated nuts. This condition, if not corrected, could result in HPC 7

th

stage IB rotor fractures. We are issuing this AD to prevent HPC 7

th stage IB rotor

fractures, which could lead to uncontained engine failure and damage to the airplane.

Related Service Information under 1 CFR Part 51

We reviewed PW Engineering Authorization (EA) No. 15MM008, Revision A, 

dated March 24, 2015. We also reviewed PW Service Bulletin (SB) No. PW6ENG 72-46, 

dated March 5, 2015. The EA describes procedures for BSIs of the HPC 7

th stage IB rotor

aft integral arm for cracks using the split-case method. The SB describes removal and 

replacement of the HPC 7

th stage IB rotor, removal of the HPC 7th stage IB rotor silverplated nuts, and the installation of non-silver plated nuts. 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 of this AD.

FAA’s Determination

We are issuing 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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AD Requirements

This AD requires initial and repetitive BSIs of the HPC 7

th stage IB rotor. This 

AD also requires as terminating action to replace the HPC 7th stage IB rotor and HPC 7th

stage IB rotor silver-plated nuts with non-silver-plated nuts.

FAA’s Justification and Determination of the Effective Date

No domestic operators use this product. Therefore, we find that notice and

opportunity for prior public comment are unnecessary and that good cause exists for 

making this amendment effective in less than 30 days.

Comments Invited

This AD is a final rule that involves requirements affecting flight safety and was 

not preceded by notice and an opportunity for public comment. However, we invite you 

to send any written data, views, or arguments about this AD. Send your comments to an 

address listed under the ADDRESSES section. Include “Docket No. FAA-2015-0266; 

Directorate Identifier 2015-NE-03-AD” at the beginning of your comments. We 

specifically invite comments on the overall regulatory, economic, environmental, and 

energy aspects of this AD. We will consider all comments received by the closing date 

and may amend this 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 AD.

Costs of Compliance

We estimate that this AD will affect 0 engines installed on airplanes of U.S. 

registry. We also estimate that it would take about 8 hours per engine to comply with this 

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

cost of this AD to U.S. operators to be $0.
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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.
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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

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):

2015-12-10 Pratt & Whitney Division: Amendment 39-18185; Docket 

No. FAA-2015-0266; Directorate Identifier 2015-NE-03-AD.

(a) Effective Date

This AD is effective [INSERT DATE 15 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER].

(b) Affected ADs

None.

(c) Applicability

This AD applies to all Pratt & Whitney Division (PW) PW6122A and PW6124A 

turbofan engines with high-pressure compressor (HPC) 7

th stage integrally bladed (IB) 

rotor, part number (P/N) 5495637, installed.

(d) Unsafe Condition

This AD was prompted by reports of crack finds in the HPC 7

th stage IB rotor. We 

are issuing this AD to prevent HPC 7

th stage IB rotor fractures, which could lead to 

uncontained engine failure and damage to the airplane.
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(e) Compliance

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

(1) Within 180 cycles after the effective date of this AD or within 6,500 cycles 

accumulated on the HPC 7th stage IB rotor, whichever occurs later, borescope inspect the 

HPC 7th stage IB rotor for cracks. Use Appendix 1, paragraphs 5 and 6 of PW

Engineering Authorization 15MM008, Revision A, dated March 24, 2015, to do your 

inspection. Thereafter, repeat the inspection at every 1,000 cycles since last inspection.

(2) If any crack is detected on the HPC 7th stage IB rotor, then before further 

flight, replace the HPC 7th stage IB rotor with a part eligible for installation.

(f) Mandatory Terminating Action

(1) At the next shop visit after the effective date of this AD:

(i) Replace the affected HPC 7

th stage IB rotor, P/N 5495637, with a new, zerotime, HPC 7

th stage IB rotor, P/N 5495637, and

(ii) Remove the HPC 7th stage IB rotor silver-plated nuts, P/N 4301682, and 

replace with non-silver-plated nuts. Use the Accomplishment Instructions of PW Service 

Bulletin No. PW6ENG 72-46, dated March 5, 2015 to perform the removal and 

replacement.

(g) Definition

For the purposes of this AD 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. The separation of engine flanges solely for the purposes of transportation without 

subsequent engine maintenance, is not 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.
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(i) Related Information

For more information about this AD, contact Wego Wang, Aerospace Engineer, 

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

Executive Park, Burlington, MA 01803; phone: 781-238-7134; fax: 781-238-7199; email: 

wego.wang@faa.gov.

(j) 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 Division (PW) Engineering Authorization No. 15MM008, 

Revision A, dated March 24, 2015.

(ii) PW Service Bulletin No. PW6ENG 72-46, dated March 5, 2015.

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

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.

(5) You may view this service information at the National Archives and Records 

Administration (NARA). For information on the availability of this material at NARA, 

call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibrlocations.html.
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Issued in Burlington, Massachusetts, on June 9, 2015.

Ann C. Mollica,

Acting Directorate Manager, Engine & Propeller Directorate,

Aircraft Certification Service.