Document ID: FAA-2015-7491-0009
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: General Electric Company Turbofan Engines
Posted Date: 2016-06-24T04:00Z

[Federal Register Volume 81, Number 122 (Friday, June 24, 2016)]
[Rules and Regulations]
[Pages 41208-41211]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-14474]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-7491; Directorate Identifier 2015-NE-39-AD; 
Amendment 39-18569; AD 2016-13-05]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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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 8-10 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.

DATES: This AD is effective July 29, 2016.

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 Avenue, 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 USIs 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 (P/Ns) 1844M90G01 and 
1844M90G02 are not required 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, 
P/N 1694M80G04.
    We disagree. HPC stage 8-10 spool P/Ns 1844M90G01 and 1844M90G02 
are susceptible to the same failure mode as HPC stage 8-10 spool, P/N 
1694M80G04. However, we

[[Page 41209]]

acknowledge that the one-time inspection is not needed for the majority 
of HPC stage 8-10 spool P/Ns 1844M90G01 and 1844M90G02. Therefore, we 
revised paragraph (e)(1) of this AD to apply to only specific serial 
numbers (S/Ns) of P/Ns 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.
    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, P/N 1694M80G04, and specific S/Ns of 
HPC stage 8-10 spool, P/Ns 1844M90G01 and 1844M90G02, that were 
manufactured using the older process.

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.

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,
    (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

[[Page 41210]]

    (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

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  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 July 29, 2016.

(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) stage 8-10 spool, part numbers (P/Ns) 
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, P/N 1694M80G04, all serial numbers 
(S/Ns), or HPC stage 8-10 spool, P/N 1844M90G01 or 1844M90G02, with 
a S/N 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.

                                                  Figure 1 to Paragraph (e)--HPC Stage 8-10 Spool S/Ns
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
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           Part Nos.                                                                   Serial Nos.
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1844M90G01.....................  GWN005MF                 GWNBK753                GWNBS077                GWNBS497                GWNBS724
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                 GWN005MG                 GWNBK754                GWNBS078                GWNBS499                GWNBS794
                                 GWN0087M                 GWNBK841                GWNBS079                GWNBS500                GWNBS810
                                 GWN0087N                 GWNBK842                GWNBS080                GWNBS501                GWNBS811
                                 GWN00DGK                 GWNBK843                GWNBS081                GWNBS502                GWNBS812
                                 GWN00DGL                 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.....................  GWN00C2T                 GWN01C5N                GWN02N8D                GWN03RTM                GWN04E21
                                 GWN00C2V                 GWN01GE2                GWN02T3R                GWN03RTP                GWN04GHT
                                 GWN00G2N                 GWN01GE3                GWN02WGM                GWN040RL                GWN04GHW
                                 GWN00G2P                 GWN01GE4                GWN0311K                GWN040RM                GWN04GJ0
                                 GWN00PFP                 GWN01GE6                GWN035PP                GWN040RN                GWN04JW6
                                 GWN00PFR                 GWN01WH1                GWN038TD                GWN040RP                GWN04JW7
                                 GWN00T2N                 GWN02688                GWN039TG                GWN04202                GWN04JW8
                                 GWN00YHV                 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, P/N 1694M80G04, 1844M90G01, 
or 1844M90G02, 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.

(f) Installation Prohibition

    After the effective date of this AD, do not re-install into any 
engine, any HPC stage 8-10 spool, P/Ns 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 
Avenue, Burlington, MA 01803;

[[Page 41211]]

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.
[FR Doc. 2016-14474 Filed 6-23-16; 8:45 am]
 BILLING CODE 4910-13-P