[Docket No. FAA-2015-3585; Directorate Identifier 2015-NE-22-AD) 

RIN 2120:.AA64 

Ainvorthiness Directives; Engine Alliance 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 certain 

Engine Alliance (EA) GP7270 turbofan engines. This proposed AD was prompted by the 

manufacturer informing us that the inspection and repair criteria in the maintenance 

manual for aft bolt holes of the high-pressure compressor (HPC) cone shaft on the 

affected engines is incorrect. This proposed AD would require inspection of the HPC 

cone shaft and repair of affected parts, if needed. We are proposing this AD to prevent 

failure of the HPC cone shaft, which could lead to uncontained engine failure and 

damage to the airplane. 

DATES: We must receive comments on this proposed AD by (fNSERT DATE 60 

DAYS AFTER DATE OF PUBLICA TTON TN 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. 

• Fax: 202-493-2251. • Mail: U.S. Department ofTransportation, Docket Operations. M-30, West 

Building Ground Floor, Room Wl2-140, 1200 New Jersey Avenue SE., Washington, DC 

20590. 
help24@pw.utc.com; website: sp.engineallianceportal.com. 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. F AA-2015-3585; 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: Martin Adler, Aerospace Engineer, 

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

01803; phone: 781-238-7157; fax: 781-238-7199; email: martin.adler@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-2015-3585; Directorate Identifier 2015-NE-22-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 

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also post a report summarizing each substantive verbal contact we receive about this 

proposed AD. 

Discussion 

We learned from the manufacturer that the inspection criteria and the repair 

procedures for the aft bolt holes of the HPC cone shaft, also referred to as the "HPC 

forward stub shaft," were listed incorrectly in the maintenance manual for the Engine 

Alliance GP7270 turbofan engines. HPC cone shafts inspected or repaired using the 

incorrect criteria in the maintenance manual could result in premature cracking of these 

parts. This condition, if not corrected, could result in failure of the I IPC cone shaft, which 

could lead to uncontained engine failure and damage to the airplane. 

Relevant Service Information under 1 CFR Part 51 

Engine Alliance has issued EA Service Bulletin (SB) No. EAGP?-72-329, dated 

July 21, 2015; and EA SB No. EAGP?-72-330, dated July 21, 2015. The SBs describe 

procedures for shotpeening and inspection of the HPC cone shaft. 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 NPRM. 

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

U.S. registry. The average labor rate is $85 per hour. Based on these figures, we estimate 

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

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 1 06, describes the authority of the FAA Administrator. 

Subtitle Vll: Aviation Programs, describes in more detail the scope of the Agency's 

authority. 

We are issuing this rulemaking under the authority described in Subtitle VIT, 

Part A, Subpart III, Section 44 701: "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, 

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

government. 

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

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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- AIRWORTffiNESS 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): 

Engine Alliance: Docket No. FAA-2015-3585; Directorate Identifier 2015-NE-22-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. 

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This AD was prompted by the manufacturer informing us that the inspection and 

repair criteria in the maintenance manual for aft bolt holes of the HPC cone shaft on the 

affected engines is incon-ect. We are issuing this AD to prevent failure of the HPC cone 

shaft, 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 HPC cone shafts with serial numbers listed in EA Service Bulletin (SB) 

No. EAGP7-72-330, dated July 21,2015, inspect the inner diameter ofthe HPC cone 

shaft aft bolt holes for nicks, dents, and scratches before accumulating 9,000 cycles since 

new (CSN). Do not reinstall the HPC cone shaft if the aft bolt hole has a nick, dent, or 

scratch that is greater than 0.002 inches in depth. 

(2) For HPC cone shafts with serial numbers listed in EA SB No. EAGP7-72-329, 

dated July 21, 2015, shot peen the HPC cone shaft aft bolt holes before accumulating 

9,000 CSN. Use paragraph 1 of the Accomplishment Instructions in EA SB No. EAGP7-

72-329 to do the shotpeening. (f) Installation Prohibition 

After the effective date of this AD, do not install an HPC cone shaft onto an 

engine with the following: 

(1) a nick, dent, or scratch in an HPC cone shaft aft bolt hole that is greater than 

0.002 inches in depth; or 

(2) any repair of an HPC cone shaft aft bolt hole that did not include shot peening. 

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(h) Related Information 

(1) For more information about this AD, contact Martin Adler, Aerospace 

Engineer, Engine & Propeller Directorate, FAA, 12 New England Executive Park, 

Burlington, MA 01803; phone: 781-238-7157; fax: 781-238-7199; email: 

martin.adler@faa.gov. 

(2) EA SB No. EAGP7-72-329, dated July 21, 2015; and EA SB No. EAGP7-72-

330, dated July 21, 2015, can be obtained from EA using the contact information in 

paragraph (h)(3) of this proposed AD. 

(3) For service information identified in this AD, contact Engine Alliance, 400 

Main St., East Hartford, CT 06108, MIS 169-10 phone: 800-565-0140; email: 

help24@pw. utc.com; website: sp.engineallianceportal.com. 

(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 781-23 8-7125. 

Issued in Burlington, Massachusetts, on September 24, 2015. 

Colleen M. D' Alessandro, 

Directorate Manager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

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