81 FR 9751 - Airworthiness Directives; General Electric Company Turbofan Engines

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration

Federal Register Volume 81, Issue 38 (February 26, 2016)

We are adopting a new airworthiness directive (AD) for all General Electric Company (GE) GEnx-1B54, -1B58, -1B64, -1B67, and -1B70 turbofan engine models. This AD was prompted by reports of two separate, single engine in-flight shutdowns (IFSDs) caused by high-pressure turbine (HPT) rotor stage 1 blade failure. This AD requires inspection and conditional removal of affected HPT rotor stage 1 blades. We are issuing this AD to prevent failure of the HPT rotor stage 1 blades, which could lead to failure of one or more engines, loss of thrust control, and damage to the airplane.

[Federal Register Volume 81, Number 38 (Friday, February 26, 2016)]
[Rules and Regulations]
[Pages 9751-9753]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2016-04031]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-2984; Directorate Identifier 2015-NE-21-AD; 
Amendment 39-18405; AD 2016-04-11]
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) GEnx-1B54, -1B58, -1B64, -1B67, and -1B70 
turbofan engine models. This AD was prompted by reports of two 
separate, single engine in-flight shutdowns

[[Page 9752]]

(IFSDs) caused by high-pressure turbine (HPT) rotor stage 1 blade 
failure. This AD requires inspection and conditional removal of 
affected HPT rotor stage 1 blades. We are issuing this AD to prevent 
failure of the HPT rotor stage 1 blades, which could lead to failure of 
one or more engines, loss of thrust control, and damage to the 
airplane.

DATES: This AD is effective April 1, 2016.

ADDRESSES: For service information identified in this final rule, 
contact General Electric Company, GE Aviation, Room 285, 1 Neumann Way, 
Cincinnati, OH 45215; phone: 513-552-3272; email: 
[email protected]. You may view this service information at 
the FAA, Engine & Propeller Directorate, 1200 District Avenue, 
Burlington, MA 01803. For information on the availability of this 
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-
2984; 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: Christopher McGuire, Aerospace 
Engineer, Engine Certification Office, FAA, Engine & Propeller 
Directorate, 1200 District Avenue, Burlington, MA 01803; phone: 781-
238-7120; fax: 781-238-7199; email: [email protected].

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 GEnx-1B54, -1B58, -
1B64, -1B67, and -1B70 turbofan engine models. The NPRM published in 
the Federal Register on August 27, 2015 (80 FR 51965). The NPRM was 
prompted by reports of two separate, single engine IFSDs caused by HPT 
rotor stage 1 blade failure. The NPRM proposed to require inspection 
and conditional removal of affected HPT rotor stage 1 blades. We are 
issuing this AD to correct the unsafe condition that could result in 
failure of the HPT rotor stage 1 blades, which could lead to failure of 
one or more engines, loss of thrust control, 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 proposal 
and the FAA's response to each comment.

Support for the NPRM

    The National Transportation Safety Board (NTSB) expressed support 
for the NPRM (80 FR 51965).

Request To Change Applicability

    United Airlines (United) requested that the Applicability paragraph 
be changed to more appropriately address engine models. United stated 
that the GEnx-1B54 and GEnx-1B58 be removed and GEnx-1B64G03, 1B64G04, 
1B67G03, 1B67G04, 1B70G03 and 1B70G04 be added to paragraph (c) 
Applicability. United indicated this change would improve clarity and 
accomplishment of the AD.
    We disagree. This AD applies to all GE GEnx-1B54, -1B58, -1B64, -
1B67, and -1B70 turbofan engine models, as listed in the GEnx type 
certificate data sheet. We did not change this AD.

Request To Change Compliance

    United requested that the Compliance paragraph be changed to 
clarify maintenance actions. United requested that in paragraph (e) the 
phrase, `` . . . remove the cracked blade'' be changed to read, `` . . 
. remove the engine containing the cracked blade.'' United reasoned 
that removing the cracked blade is not a maintenance option.
    We partially agree. We agree with changing the compliance language 
to include disposition of a cracked blade. We disagree with using the 
phrase, `` . . . remove the engine containing the cracked blade'' 
because removal of the cracked blade addresses the unsafe condition.
    We revised paragraphs (e)(1)(i) and (e)(1)(ii) of this AD to 
include, `` . . . remove the cracked blade from service. . . .''

Request To Change the Summary and Unsafe Condition

    Boeing and General Electric Company (GE) requested that the Summary 
and Unsafe Condition paragraphs be clarified to reflect that two 
separate, single engine IFSDs occurred, prompting the need for this AD.
    We agree. We changed the Summary and Unsafe Condition paragraphs of 
this AD to read: ``This AD was prompted by reports of two separate, 
single engine in-flight shutdowns, caused by HPT rotor stage 1 blade 
failure. . . .''

Request To Change the Cost of Compliance

    Boeing requested that the Costs of Compliance paragraph 
specifically state that the projected costs are for only the initial 
inspection and not for repetitive inspections. Boeing indicated this is 
needed to clarify the cost of compliance.
    We agree. We changed the Costs of Compliance paragraph of this AD 
to include, ``We also estimate that it will take about 1 hour per 
engine to comply with the initial inspection in this AD.''

Request To Change Compliance Time

    Japan Airlines (JAL) and GE suggested that in paragraph (e)(1) 
Compliance, the need to inspect within 1,000 cycles since new (CSN) may 
not be representative of the fleet.
    We disagree. The initial blade inspection compliance time was based 
on the safety evaluation of the known failures. Any person may make a 
request for an Alternative Method of Compliance (AMOC) to the 
compliance times of this AD using the procedures listed herein. We did 
not change this AD.

Request To Change Compliance

    GE requested that the Compliance paragraph be changed to clarify 
that the criteria of multiple cracks should be based on an individual 
blade and not multiple blades, each with a single crack.
    We agree. We changed paragraph (e)(1)(i) of this AD to read: ``. . 
. , or if more than one axial crack of any length is found on one 
blade, remove the cracked blade from service before further flight.''

Revision to Service Information

    We revised the service information in the Related Information 
section of this AD to Revision 01 of GE GEnx-1B Service Bulletin (SB) 
No. 72-0267 R01, dated August 10, 2015. GE made an editorial change to 
this SB that did not affect its contents.

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 (80 FR 51965) for correcting the unsafe condition; and

[[Page 9753]]

     Do not add any additional burden upon the public than was 
already proposed in the NPRM (80 FR 51965).
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this AD.

Costs of Compliance

    We estimate that this AD will affect 4 engines installed on 
airplanes of U.S. registry. We also estimate that it will take about 1 
hour per engine to comply with the initial inspection in this AD. The 
average labor rate is $85 per hour. Based on these figures, we estimate 
the total cost of this AD to U.S. operators to be $340.

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 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.

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):

2016-04-11 General Electric Company: Amendment 39-18405; Docket No. 
FAA-2015-2984; Directorate Identifier 2015-NE-21-AD.

(a) Effective Date

    This AD is effective April 1, 2016.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all General Electric Company (GE) GEnx-1B54, 
-1B58, -1B64, -1B67, and -1B70 turbofan engine models with high-
pressure turbine (HPT) rotor stage 1 blade, part number 2305M26P06, 
installed.

(d) Unsafe Condition

    This AD was prompted by reports of two separate, single engine 
in-flight shutdowns, caused by HPT rotor stage 1 blade failure. We 
are issuing this AD to prevent failure of the HPT rotor stage 1 
blades, which could lead to failure of one or more engines, loss of 
thrust control, and damage to the airplane.

(e) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.
    (1) Perform an initial borescope inspection (BSI) of the convex 
surface of the HPT rotor stage 1 blades for axial cracks from the 
platform to 30% span, within 1,000 blade cycles since new or 25 
cycles after the effective date of this AD, whichever occurs later, 
and disposition as follows:
    (i) If any axial crack with a length greater than or equal to 
0.3 inch is found, or if any axial crack of any length turning in a 
radial direction is found, or if more than one axial crack of any 
length is found on one blade, remove the cracked blade from service 
before further flight.
    (ii) If an axial crack is found with a length greater than or 
equal to 0.2 inch and less than 0.3 inch, remove the cracked blade 
from service within 10 blade cycles.
    (iii) If an axial crack is found with a length greater than or 
equal to 0.1 inch and less than 0.2 inch, inspect the cracked blade 
within 50 blade cycles since last inspection (CSLI).
    (iv) If an axial crack is found with a length less than 0.1 
inch, inspect the cracked blade within 100 blade CSLI.
    (v) If no cracks were found, perform a BSI of the blades within 
125 blade CSLI.
    (2) Thereafter, perform a repetitive BSI of the convex surface 
of the HPT rotor stage 1 blades for axial cracks from the platform 
to 30% span within 125 blade CSLI and disposition as specified in 
paragraphs (e)(1)(i) through (e)(1)(v) of this AD, or remove the 
blades from service.

(f) Definition

    For the purpose of this AD, a ``blade cycle'' is defined as the 
number of engine cycles that a set of rotor blades has accrued, 
regardless of the engine(s) in which they have operated.

(g) Alternative Methods of Compliance (AMOCs)

    The Manager, Engine Certification Office, FAA, may approve AMOCs 
to this AD. Use the procedures found in 14 CFR 39.19 to make your 
request. You may email your request to: [email protected].

(h) Related Information

    (1) For more information about this AD, contact Christopher 
McGuire, Aerospace Engineer, Engine Certification Office, FAA, 
Engine & Propeller Directorate, 1200 District Avenue, Burlington, MA 
01803; phone: 781-238-7120; fax: 781-238-7199; email: 
[email protected].
    (2) GE GEnx-1B Service Bulletin No. 72-0267 R01, dated August 
10, 2015 can be obtained from GE using the contact information in 
paragraph (h)(3) of this AD.
    (3) For service information identified in this AD, contact 
General Electric Company, GE Aviation, Room 285, 1 Neumann Way, 
Cincinnati, OH 45215; phone: 513-552-3272; email: 
[email protected].
    (4) You may view this service information at the FAA, Engine & 
Propeller Directorate, 1200 District Avenue, Burlington, MA. For 
information on the availability of this material at the FAA, call 
781-238-7125.

    Issued in Burlington, Massachusetts, on February, 18, 2016.
Ann C. Mollica,
Acting Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-04031 Filed 2-25-16; 8:45 am]
BILLING CODE 4910-13-P