DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[4910-13-P] 

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

39-18569; AD 2016-13-05] 

RIN 2120-AA64 

Ainvorthiness Directives; General Electric Company Turbofan Engines 

AGENCY: Federal Aviation Administration (FAA), DOT. 

ACTION: Final rule. 

SUMMARY: We are adopting 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 AD was prompted by an uncontained failure of the high-pressure 

compressor (HPC) stage 8-10 spool, leading to an airplane fire. This AD requires eddy 

current inspection (ECI) or ultrasonic inspection (USI) of the HPC stage 8-1 0 spool and 

removing from service those parts that fail inspection. 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. 

DATES: This AD is effective [INSERT DATE 35 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. 

ADDRESSES: See the For Further Information Contact section. 

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 AD, the regulatory evaluation, any comments 

received, and other information. The address for the Docket Office (phone: 
800-647-5527) is Document Management Facility, U.S. Department of Transportation, 

Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 

Jersey Avenue SE., Washington, DC 20590. 

FOR FURTHER INFORMATION CONTACT: John Frost, Aerospace Engineer, 

Engine Certification Office, FAA, 1200 District A venue, Burlington, MA 01803; phone: 

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

SUPPLEMENTARY INFORMATION: 

Discussion 

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by 

adding an AD that would apply to all GE GE90-76B, GE90-77B, GE90-85B, GE90-90B, 

and GE90-94B turbofan engines. The NPRM published in the Federal Register on 

January 13, 2016 (81 FR 1582). The NPRM was prompted by an uncontained failure of 

the HPC stage 8-10 spool, leading to an airplane fire. The NPRM proposed to require 

ECis or US Is of the HPC stage 8-10 spool and removing from service those parts that fail 

inspection. 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. 

Comments 

We gave the public the opportunity to participate in developing this AD. The 

following presents the comments received on the NPRM (81 FR 1582, January 13, 2016) 

and the FAA's response to each comment. 

Support for the NPRM (81 FR 1582, January 13, 2016) 

The Air Line Pilots Association expressed support for the NPRM (81 FR 1582, 

January 13, 2016). 

Request to Change Applicability 

British Airways, United Airlines, and The Boeing Company commented that HPC 

stage 8-10 spool, part numbers (PINs) 1844M90G01 and 1844M90G02 are not required 

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in the Applicability paragraph of this AD. They noted that the associated AD 2015-27-01, 

(81 FR 1291, January 12, 2016) and the precipitating event involved only HPC stage 8-10 

spool, PIN 1694M80G04. 

We disagree. HPC stage 8-10 spool PINs 1844M90G01 and 1844M90G02 are 

susceptible to the same failure mode as HPC stage 8-10 spool, PIN 1694M80G04. 

However, we acknowledge that the one-time inspection is not needed for the majority of 

HPC stage 8-10 spool PINs 1844M90G01 and 1844M90G02. Therefore, we revised 

paragraph (e)(1) of this AD to apply to only specific serial numbers (SINs) of PINs 

1844M90G01 and 1844M90G02 for the one-time inspection. 

Request to Change Compliance Time 

British Airways requested that we clarify if a repetitive on-wing inspection is 

required. They reasoned that the service information lists the on-wing inspection as one 

time only. 

We disagree. Paragraph (e)( 1) of this AD mandates that specific parts be 

inspected prior to a cycle limit. This initial inspection may be performed on wing using 

USI or at shop visit using ECI. Repetitive inspections prior to shop visit are not 

mandated, however we acknowledge that GE has commented that they should be 

performed. We did not change this AD. 

Request to Change Terminating Action 

GE requested that we remove the repetitive shop visit inspection from the 

Compliance section of this AD and instead mandate that the airworthiness limitations 

section (ALS) of the engine manual include the repetitive inspections. They also 

requested that the Summary section and Related Information section of this AD be 

revised to reflect this change. They reasoned that this will allow a terminating action for 

this AD. 

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We disagree. At this time we do not feel that a change to the ALS is appropriate 

as root cause has not been determined. We did not change this AD. 

Request to Change Installation Prohibition 

GE requested that we clarify that the installation prohibition does not apply to 

new parts. They stated that new parts do not need to be inspected prior to installation. The 

inspections are only applicable to parts that have been used in service. 

We agree. We revised paragraph (f) of this AD to specify that inspections are only 

required for parts that have been used in service. 

Request to Change Service Information 

GE and British Airways requested that we revise the Related Service Information 

paragraph of this AD to remove the reference to Engine Manual, Chapter 72-00-31, 

Special Procedure 007 and add a reference to GE GE90 SB 72-1146. They reasoned that 

the Special Procedure is considered an additional inspection technique and the other 

inspection procedures listed provide full detection capability of defects in the area of 

concern. 

We disagree. The service information is not incorporated by reference in this AD 

and was previously included for information purposes only. However, to preclude any 

confusion on this point, we removed all service information from the Related Information 

section of this AD. 

Request to Change Applicability 

GE requested that we reduce the applicability for the initial inspection. GE has 

determined that an older manufacturing process may be a contributor to part failure and 

that all parts manufactured using this process should be inspected prior to shop visit. 

We agree. We revised the applicability of the initial inspection to include all HPC 

stage 8-10 spool, PIN 1694M80G04, and specific SINs ofHPC stage 8-10 spool, PINs 

1844M90G01 and 1844M90G02, that were manufactured using the older process. 

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Request to Change Compliance Time 

GE has requested that the initial USI compliance time be reduced and to add 

repetitive inspections every 500 cycles until shop visit ECI for the parts manufactured 

using the older manufacturing process noted above. GE has determined that the smallest 

detectable flaw using USI with the compressor blades installed is larger than what was 

used in the prior analysis. 

We partially agree. We agree that the USI inspection is not as capable as what 

was used in the prior analysis. We also agree that a reduced threshold for initial 

inspection is appropriate. So, we reduced the initial inspection threshold in paragraph 

(e)(1) of this AD from 10,500 cycles to 9,000 cycles and removed USI as an option for 

the inspections in paragraph (e)(2) of this AD. We disagree with including the 500 cycle 

repetitive inspections; however, repetitive inspections would be a consideration for 

additional rulemaking. 

Conclusion 

We reviewed the relevant data, considered the comments received, and 

determined that air safety and the public interest require adopting this AD with the 

changes described previously. We have determined that these minor changes: 

• Are consistent with the intent that was proposed in the NPRM (81 FR 

1582, January 13, 2016) for correcting the unsafe condition; and 

• Do not add any additional burden upon the public than was already 

proposed in the NPRM (81 FR 1582, January 13, 2016). 

We also determined that these changes will not increase the economic burden on 

any operator or increase the scope of this AD. 

Interim Action 

GE is determining the root cause for the unsafe condition identified in this AD. 

Once a root cause is identified, we will consider additional rulemaking. 

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Costs of Compliance 

We estimate that this AD affects 54 engines installed on 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 this 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 

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, 

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(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, 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. 

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): 

2016-13-05 General Electric Company: Amendment 39-18569; Docket 

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

(a) Effective Date 

This AD is effective [INSERT DATE 35 DAYS AFTER DATE OF 

PUBLICATION IN 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 

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

1844M90G02, installed. 

(d) Unsafe Condition 

This AD was prompted by an uncontained failure of the 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) For HPC stage 8-10 spool, PIN 1694M80G04, all serial numbers (SINs), or 

HPC stage 8-10 spool, PIN 1844M90G01 or 1844M90G02, with a SIN listed in Figure 1 

to paragraph (e) of this AD; perform an eddy current inspection (ECI) or ultrasonic 

inspection (USI) of the stage 8 aft web upper face, after reaching 8,000 cycles since new 

(CSN), but, before exceeding 9,000 CSN, or within 500 cycles in service after the 

effective date of this AD, whichever occurs later. 

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Figure 1 to Paragraph (e)- HPC Stage 8-10 Spool SINs 

Part Numbers Serial Numbers 

1844M90G01 GWNOOSMF GWNBK753 GWNBS077 GWNBS497 GWNBS724 

GWNOOSMG GWNBK754 GWNBS078 GWNBS499 GWNBS794 

GWN0087M GWNBK841 GWNBS079 GWNBS500 GWNBS810 

GWN0087N GWNBK842 GWNBS080 GWNBS501 GWNBS811 

GWNOODGK GWNBK843 GWNBS081 GWNBS502 GWNBS812 

GWNOODGL GWNBK844 GWNBS157 GWNBS609 GWNBS813 

GWNBJ992 GWNBK952 GWNBS158 GWNBS610 GWNBS814 

GWNBK667 GWNBK953 GWNBS159 GWNBS611 GWNBS910 

GWNBK674 GWNBK954 GWNBS160 GWNBS612 GWNBS911 

GWNBK675 GWNBK955 GWNBS266 GWNBS613 GWNBS912 

GWNBK743 GWNBK956 GWNBS267 GWNBS614 GWNBS914 

GWNBK744 GWNBK957 GWNBS268 GWNBS721 GWNBS915 

GWNBK751 GWNBK958 GWNBS269 GWNBS722 GWNBS982 

GWNBK752 GWNBK959 GWNBS270 GWNBS723 GWNBS983 

1844M90G02 GWNOOC2T GWN01C5N GWN02N8D GWN03RTM GWN04E21 

GWNOOC2V GWN01GE2 GWN02T3R GWN03RTP GWN04GHT 

GWNOOG2N GWN01GE3 GWN02WGM GWN040RL GWN04GHW 

GWNOOG2P GWN01GE4 GWN0311K GWN040RM GWN04GJO 

GWNOOPFP GWN01GE6 GWN035PP GWN040RN GWN04JW6 

GWNOOPFR GWN01WH1 GWN038TD GWN040RP GWN04JW7 

GWNOOT2N GWN02688 GWN039TG GWN04202 GWN04JW8 

GWNOOYHV GWN02689 GWN03G2R GWN0435W GWN04L7K 

GWN0125G GWN0268A GWN03G2W GWN04360 GWN04L7L 

GWN0125H GWN02DP2 GWN03G30 GWN04361 GWN04MT7 

GWN0166K GWN02DP3 GWN03JPC GWN04362 GWN04MT8 

GWN01C5K GWN02F9F GWN03JPD GWN04ATG GWNBS984 

GWN01C5L GWN02F9G GWN03N8P GWN04ATH 

GWN01C5M GWN02L9T GWN03N8R GWN04E20 

(2) For all HPC stage 8-10 spools, PIN 1694M80G04, 1844M90G01, or 

1844 M90G02, perform an ECI of the stage 8 aft web upper face of the HPC stage 8-10 

spool at each shop visit. 

(3) Remove from service any HPC stage 8-10 spool that fails the inspection 

required by paragraphs (e)(1) or (e)(2) of this AD, and replace with a spool eligible for 

installation. 

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(f) Installation Prohibition 

After the effective date of this AD, do not re-install into any engine, any HPC 

stage 8-10 spool, PINs 1694M80G04, 1844M90G01, or 1844M90G02, unless the spool 

has passed an ECI of the stage 8 aft web upper face as specified in paragraph (e)( 1) or 

(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 

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

Engine Certification Office, FAA, 1200 District A venue, Burlington, MA 01803; phone: 

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

(j) Material Incorporated by Reference 

None. 

Issued in Burlington, Massachusetts, on June 15, 2016. 

Colleen M. D' Alessandro, 

Manager, Engine & Propeller Directorate, 

Aircraft Certification Service. 

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