[Docket No. FAA-2015-3713; Directorate Identifier 2015-NE-23-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 

reports of the installation of non-conforming honeycomb seals in the high-pressure 

compressor (HPC) adjacent to the HPC rotor stage 2 to 5 spool and stage 7 to 9 spool. 

This proposed AD would require removal and replacement of the affected HPC rotor 

stage 2 to 5 and stage 7 to 9 spools. We are proposing this AD to prevent failure of the 

HPC rotor stage 2 to 5 and stage 7 to 9 spools, which could lead to 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 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 W12-140, 1200 New Jersey Avenue SE., Washington, DC 

20590. 
email: help24@pw.utc.com; website: www.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 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 by 

searching for and locating Docket No. FAA-2015-3713; 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-2015-3713; Directorate Identifier 2015-NE-23-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 

2 
also post a report summarizing each substantive verbal contact we receive about this 

proposed AD. 

Discussion 

We leamed from the manufacturer that non-conforming honeycomb seals were 

installed in the affected HPCs adjacent to the HPC rotor stage 2 to 5 spools and stage 7 to 

9 spools. The honeycomb seals in the HPC were machined to an incorrect radial height 

which resulted in reduced clearances between the honeycomb and the rotating spools. 

This error could lead to cracks on the spools prior to reaching their full life. This 

condition, if not corrected, could result in failure of the HPC rotor stage 2 to 5 and stage 7 

to 9 spools, 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. EAGP7-72-327, dated 

July 21, 2015; and SB No. EAGP7-72-328, dated July 21,2015. The SBs describe 

procedures for removal and replacement of HPC rotor stage 2 to 5 spools and HPC rotor 

stage 7 to 9 spools, respectively. 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 document. 

FAA's Determination 

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

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

products of the same type design. 

3 
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 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 Ill, 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, 

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

government. 

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

4 
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): 

Engine Alliance: Docket No. FAA-2015-3713; Directorate Identifier 2015-NE-23-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. 

5 
382-104-807-0, with a serial number (SIN) listed in EA Service Bulletin (SB) No. 

EAGP7-72-327, dated July 21, 2015; or 

(2) an HPC rotor stage 7 to 9 spool, PIN 2031 M90G04, 2031 M90G05, or 

2031M90G07, with an SIN listed in EA SB No. EAGP7-72-328, dated July 21,2015. 

(d) Unsafe Condition 

This AD was prompted by reports of the installation of non-conforming 

honeycomb seals in the HPC adjacent to the HPC rotor stage 2 to 5 spool and stage 7 to 9 

spool. We are issuing this AD to prevent failure of the HPC rotor stage 2 to 5 spools and 

stage 7 to 9 spools, 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. 

Within 30 days after the effective date of this AD or before accumulating 2, 100 engine 

cycles since the last disassembly of the compressor module of the engine, whichever 

occurs later: 

(1) For engines with an HPC rotor stage 2 to 5 spool, PIN 382-104-807-0, 

installed with a SIN listed in EA SB No. EAGP7-72-327, dated July 21,2015, do the 

following: 

(i) Remove the HPC rotor stage 2 to 5 spool from service and replace with a part 

eligible for installation. 

(ii) Remove and replace the honeycomb seals on the HPC stage 5 vanes. 

6 
eligible for installation. 

(ii) Remove and replace the honeycomb seals on the HPC stage 6, stage 7, and 

stage 8 vanes. 

(f) Alternative Methods of Compliance (AMOCs) 

The Manager, Engine Certification Office, 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. 

(g) 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 SBs No. EAGP7-72-327, dated July 21, 2015; and No. EAGP7-72-328, 

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

(g)(3) of this proposed AD. 

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

Main St., East Hartford, CT 061 08, M/S 169-10, phone: 800-565-0 140; email: 

help24@pw.utc.com; website: www.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 781-238-7125. 

7 
Colleen M. D' Alessandro, 

Directorate Manager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

8