!Docket No. FAA-2015-4023; Directorate Identifier 2015-NE-29-AD] 

RIN 2120-AA64 

Airworthiness Directives; General Electric Company 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 General 

Electric Company (GE) CF6-80El turbofan engines with rotating compressor discharge 

pressure (CDP) seal, part number (PIN) 1669M73P02, installed. This proposed AD was 

prompted by reports from the manufacturer of cracks in the teeth of two rotating CDP 

seals found during engine shop visits. This proposed AD would require stripping of the 

coating, inspecting, and recoating the teeth of the affected rotating CDP seals. We are 

proposing this AD to prevent cracking of the CDP seal teeth, which can lead to 

uncontained part re lease, 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 ofthe 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. 
51 3-552-3272; email: aviation.fleetsupport@ge.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 tbe AD Docket 

You may examine the AD docket on the Internet at http://www.regulations.gov by 

searching for and locating Docket No. FAA-2015-4023; 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: Herman Mak, Aerospace Engineer, 

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

Executive Park, Burlington, MA 01803; phone: 781-238-7147; fax: 781-238-7199; email: 

herman.mak@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-2015-4023; Directorate Identifier 2015-NE-29-AD" at the 

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

2 
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 received reports from GE of cracks in the teeth on two rotating COP seals 

found during engine shop visits. We learned that the CUITent borazon-nickel seal tooth 

coating oxidizes during engine operation, which could lead to reduced cutting action, 

overheating of the seal teeth, and premature cracking of the seal teeth. This condition, if 

not corrected, could result in cracking of the COP seal teeth, uncontained part release, 

damage to the engine, and damage to the airplane. 

Relevant Service Information under 1 CFR Part 51 

We reviewed GE Service Bulletin (SB) No. CF6-80E 1 SIB 72-0529, Revision 1, 

dated August 21,2015. The SB describes procedures for stripping, inspecting, and 

replacing the seal tooth coating on the affected rotating COP seals. This service 

information is reasonably available because the interested parties have access to it 

through their nom1al course of business or by the means identified in the ADDRESSES 

section of this document. 

Other Related Service Information 

We reviewed GE CF6-80El (GEK99376) Engine Manual, Revision 42, dated 

March 15, 2014. The engine manual describes acceptable repair procedures for the seal 

teeth. 

3 
Proposed AD Requirements 

This proposed AD would require stripping, inspecting, and recoating the teeth on 

the affected CDP seals. 

Costs of Compliance 

We estimate that this proposed AD will affect 6 engines installed on airplanes of 

U.S. registry. We also estimate that it will take about 7 hours per engine to comply with 

this proposed AD. The average labor rate is $85 per hour. Parts would cost about $7,835 

per engine. Based on these figures, we estimate the total cost of this proposed AD to U.S. 

operators to be $50,657. 

Authority for this Rulemaking 

Title 49 of the United States Code specifies the FAA's authority to issue rules on 

aviation safety. Subtitle 1, section I 06, 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 lll, 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. Tllis 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. 

4 
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): 

5 
PUBLICATION IN THE Federal Register]. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to all General Electric Company (GE) CF6-80El turbofan 

engines with rotating compressor discharge pressure (CDP) seals, part number (PIN) 

1669M73P02, installed. 

(d) Unsafe Condition 

This AD was prompted by reports from the manufacturer of cracks in the teeth of 

two rotating CDP seals found during engine shop visits. We are issuing this AD to 

prevent cracking of the CDP seal teeth, which can lead to uncontained part release, 

damage to the engine, and damage to the airplane. 

(e) Compliance 

(I) Comply with this AD within the compliance times specified, unless already 

done. 

(2) After the effective date of this AD, strip coating, inspect, and recoat the teeth 

of the rotating COP seal, PIN 1669M73P02, in accordance with paragraph 3.C.(2) of GE 

Service Bulletin (SB) No. CF6-80E 1 S/B 72-0529, Revision 1, dated August 21, 2015, as 

follows: 

(i) For engines that have had stationary COP seal, PIN 1347M28002, repaired or 

replaced, strip coating, inspect, and recoat the rotating COP seal at the next engine shop 

visit. 

6 
( 1) For the purpose of this AD, part exposure is defined as removal of the 

compressor rear frame from the high-pressure compressor module. 

(2) For the purpose of this AD, an engine shop visit is defined as the induction of 

an engine into the shop for maintenance involving the separation of pairs of major mating 

engine flanges, except that the separation of engine flanges solely for the purposes of 

transportation without subsequent engine maintenance does not constitute an engine shop 

visit. 

(g) Credit for Previous Action 

Tf you stripped, inspected, and recoated the CDP seal, PIN 1669M73P02, using 

the procedures in ESM 72-31-10, REPAIR 002 ofthe GE CF6-80El (GEK99376) 

Engine Manual, Revision 42, dated March 15, 2014, or earlier versions, then you met the 

requirements of this AD. 

(h) Alternative Methods of Compliance (AMOCs) 

The Manager, Engine Certification Office, FAA, may approve AMOCs to this 

AD. Use the procedures found in 14 CFR 3 9.19 to make your request. You may email 

your request to: ANE-AD-AMOC@faa.gov. 

(i) Related Information 

(1) For more infonnation about this AD, contact Hennan Mak, Aerospace 

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

England Executive Park, Burlington, MA 01803; phone: 781-238-7147; fax: 781-238-

7199; email: herman.mak@faa.gov. 

7 
phone: 513-552-3272; email: aviation.fleetsupport@ge.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 ofthis material at the FAA, call 781-238-7125. 

Issued in Burlington, Massachusetts, on November 4, 2015. 

Carlos A. Pestana, 

Acting Directorate Manager, Engine & Propeller Directorate, Aircraft Certification Service. 

8