14 CFR Part 39 

[Docket No. FAA-2015-7491; Directorate Identifier 2015-NE-39-AD] 

RlN 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) GE90-76B, GE90-77B, GE90-85B, GE90-90B, and GE90-94B 

turbofan engines. This proposed AD was prompted by an uncontained failure of the highpressure compressor (HPC) stage 8-10 spool, leading to an airplane fire. This proposed 

AD would require eddy current inspections (ECis) or ultrasonic inspections (USis) of the 

HPC stage 8-10 spool and removing from service those parts that fail inspection. We are 

proposing this AD to prevent failure of the HPC stage 8-10 spool, uncontained rotor 

release, 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 of the following methods: 

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

instructions for submitting comments. 

• Fax: 202-493-2251. 
Monday through Friday, except Federal holidays. 

For service information identified in this proposed-AD, contact General Electric 

Company, GE-Aviation, Room 285, 1 Neumann Way, Cincinnati, OH 45215, phone: 

513-552-3272; fax: 513-552-3329; email: geae.aoc@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, 

call781-238-7125. 

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-2015-7491; 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: John Frost, Aerospace Engineer, 

Engine Certification Office, FAA, 12 New England Executive Park, Burlington, MA 

01803; phone: 781-238-7756; fax: 781-238-7199; email: john.frost@faa.gov. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

We invite you to send any written relevant data, views, or arguments about this 

NPR1V1. Send your comments to an address listed under the ADDRESSES section. 

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comments. 

We will post all comments we receive, without change, to 

http://\VWW.regulations.gov, including any personal information you provide. We will 

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

NPRM. 

Discussion 

We received a report of an HPC stage 8-10 spool uncontained failure resulting in 

an airplane fire. Ongoing investigations have determined that a crack initiated in the stage 

8 aft web upper face of the HPC 8-10 spool and propagated until spool rupture. The root 

cause of the crack initiation is not yet known. This condition, if not corrected, could 

result in failure of the HPC stage 8-10 spool, uncontained rotor release, damage to the 

engine, and damage to the airplane. We are issuing this AD to correct the unsafe 

condition on these products. 

Related Service Information 

We reviewed the following chapters ofGE GE90 Engine Manual, GEK100700, 

Revision 66, dated September 1, 2015: 

• Chapter 72-31-08, Special Procedure 003, piece-part level ECI, 

• Chapter 72-00-31, Special Procedure 006, rotor assembly and module 

level ECI and, 

• Chapter 72-00-31, Special Procedure 007, rotor assembly level USL 

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Proposed AD Requirements 

This NPRM would require accomplishing an ECI or USI of the stage 8 aft web 

upper face of the HPC stage 8-10 spool and removing from service those parts that fail 

inspection. 

Interim Action 

We consider this proposed AD interim action. GE is determining the root cause 

for the unsafe condition identified in this proposed AD. Once a root cause is identified, 

we might consider additional rulemaking. 

Costs of Compliance 

We estimate that this proposed AD affects 54 engines installed 01:1 airplanes of 

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

this AD. The average labor rate is $85 per hour. We estimate one part will fail inspection 

at a cost of$780,000. Based on these figures, we estimate the total cost of the AD to U.S. 

operators to be $812,130. 

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 

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Regulatory Findings 

We detennined 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, 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. 

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NE

39

AD. 

(a) Comments Due Date 

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

PUBLICATION lN THE FEDERAL REGISTER]. 

(b) Affected ADs 

None. 

(c) Applicability 

This AD applies to General Electric Company (GE) GE90-76B, GE90-77B, 

GE90-85B, GE90-90B, and GE90-94B turbofan engines with a high-pressure compressor 

(HPC) 8-10 stage spool, part numbers (PINs) 1694M80G04, 1844M90G01, or 

1844M90G02, installed. 

(d) Unsafe Condition 

This AD was prompted by an uncontained failure ofthe HPC stage 8-10 spooL 

We are issuing this AD to prevent failure of the HPC stage 8-10 spool, uncontained rotor 

release, damage to the engine, and damage to the airplane. 

(e) Compliance 

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

(1) Perform an eddy current inspection (ECI) or ultrasonic inspection (USI) of the 

stage 8 aft web upper face of the HPC stage spool, before exceeding 10,500 cycles 

since new or within 500 cycles in service, after the effective date of this AD, whichever 

occurs later. 

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eligible for installation. 

(f) Installation Prohibition 

After the effective date of this AD, an HPC stage 8-10 spool, PINs 1694M80G04, 

1844M90G01, and 1844M90G02, is not eligible for installation into any engine, tmless 

the spool has passed an ECI or US! required by paragraphs ( e )(I) and ( e )(2) of this AD. 

(g) Definition 

For the purpose of this AD, an engine shop visit is the induction of an engine into 

the shop for maintenance during which the compressor discharge pressure seal face is 

exposed. 

(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. 

(i) Related Information 

(1) For more information about this AD, contact John Frost, Aerospace Engineer, 

Engine Certification Office, FAA, 12 New England Executive Park, Burlington, MA 

01803; phone: 781-238-7756; fax: 781-238-7199; email: john.frost@faa.gov. 

(2) GE GE90 Engine Manual, GEK100700, Revision 66, dated September I, 

2015, Chapter 72-31-08, Special Procedure 003, Chapter 72-00-31, Special Procedure 

006, and Chapter 72-00-31, Special Procedure 007, rotor assembly level USI can be 

obtained from General Electric Company, using the contact information in paragraph 

(i)(3) of this AD. 

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Directorate, 12 New England Executive Park, Burlington, MA. For information on the 

availability of this material at the FAA, call781-238-7125. 

Issued in Burlington, Massachusetts, on December 22,2015. 

Colleen M. D' Alessandro, 

Directorate Manager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

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