[Federal Register Volume 81, Number 16 (Tuesday, January 26, 2016)]
[Rules and Regulations]
[Pages 4165-4167]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-01268]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-3585; Directorate Identifier 2015-NE-22-AD; 
Amendment 39-18384; AD 2015-28-01]
RIN 2120-AA64


Airworthiness Directives; Engine Alliance 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 certain 
Engine Alliance (EA) GP7270 turbofan engines. This AD was prompted by 
the manufacturer informing us that the inspection criteria and repair 
procedures in the maintenance manual for aft bolt holes of the high-
pressure compressor (HPC) cone shaft on the affected engines is 
incorrect. This AD requires inspection of the HPC cone shaft and repair 
of affected parts, if needed. We are issuing this AD to prevent failure 
of the HPC cone shaft, which could lead to uncontained engine failure 
and damage to the airplane.

DATES: This AD is effective March 1, 2016.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of March 1, 
2016.

ADDRESSES: For service information identified in this AD, contact 
Engine Alliance, 400 Main St., East Hartford, CT 06108, M/S 169-10, 
phone: 800-565-0140; email: [email protected]; Internet: 
sp.engineallianceportal.com. 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.

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-
3585; 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: Kyle Gustafson, Aerospace Engineer, 
Engine & Propeller Directorate, FAA, 1200 District Avenue, Burlington, 
MA 01803; phone: 781-238-7183; 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 certain EA GP7270 turbofan 
engines. The NPRM published in the Federal Register on October 1, 2015 
(80 FR 59081). The NPRM was prompted by the manufacturer informing us 
that the inspection criteria and repair procedures in the maintenance 
manual for aft bolt holes of the HPC cone shaft, also referred to as 
the ``HPC forward stubshaft,'' for the affected engines is incorrect. 
The NPRM proposed to require inspection of the HPC cone shaft and 
repair of affected parts, if needed. We are issuing this AD to prevent 
failure of the HPC cone shaft, which could lead to uncontained engine 
failure 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 (80 
FR 59081, October 1, 2015) and the FAA's response to each comment.

Request To Add Engine Models

    EA requested that we expand the applicability to include the GP7272 
and GP7277 engine models.
    We disagree. There are no GP7272 or GP7277 engines in service nor 
have any been delivered. New engines would be delivered with corrected 
service

[[Page 4166]]

information and would not be impacted by this AD. We did not change 
this AD.

Request To Change the Unsafe Condition Statement

    EA requested that the unsafe condition statement be changed from 
``We are issuing this AD to prevent failure of the HPC cone shaft, 
which could lead to uncontained engine failure and damage to the 
airplane.'' to ``We are issuing this AD to prevent a hazardous engine 
condition.'' The reason for this request is that no HPC cone shaft 
failures have occurred in the field.
    We disagree. The unsafe condition statement describes the condition 
we are trying to prevent and is the justification for this AD. It does 
not describe what has occurred in the past. We did not change this AD.

Request To Change Various Paragraphs

    EA requested that we revise the part nomenclature in the 
Applicability, Compliance, and Installation Prohibition paragraphs and 
in the unsafe condition statement to include both ``cone shaft'' and 
``forward stubshaft.'' The part is referenced as a ``cone shaft'' in 
this AD and engine and component manuals; however, it is referred to as 
a ``forward stubshaft'' in the service bulletins (SBs).
    We disagree. The part nomenclature listed in the airworthiness 
limitations section and engine maintenance manual is ``cone shaft.'' 
The Discussion section of this AD explains that the terms ``cone 
shaft'' and ``forward stubshaft'' are synonymous. We consider including 
both terms throughout this AD unnecessary. We did not change this AD.

Request To Revise the Compliance

    EA requested that the Compliance paragraph be revised to include 
the word ``pits'' when describing the inspection criteria.
    We agree. We revised paragraph (e)(1) and (f)(1) of this AD from 
``. . . nicks, dents, and scratches . . .'' to ``. . . nicks, dents, 
pits, and scratches. . . .''

Request To Change the Compliance

    EA requested that we replace ``Do not reinstall the HPC cone shaft 
if the aft bolt hole has a nick, dent, or scratch that is greater than 
0.002 inch in depth'' in paragraph (e)(1) of this AD with ``Comply with 
the Accomplishment Instructions in EA SB No. EAGP7-72-330 if the aft 
bolt hole has a nick, dent, pit, or scratch that is greater than the 
serviceable limit.''
    We disagree. The current engine manual has an approved repair 
procedure for damage that is more severe than the installation 
requirements of this AD. It is not necessary to restate what is already 
allowed by the engine manual. We did not change this AD.

Request To Change Service Information

    EA requested that the phrase ``or later'' be used when referring to 
SBs.
    We disagree. We are only authorized to mandate use of SBs that we 
have reviewed and which are published. Since future revisions of SBs 
are not yet published, we are not authorized to mandate their use. We 
did not change this AD.

Request To Change the Installation Prohibition

    EA requested that we change the Installation Prohibition paragraph 
to read: ``After the effective date of this AD, do not install an HPC 
cone shaft onto an engine: (1) that has accumulated more than 9,000 
cycles since new that has not complied with this AD on an applicable 
part, and (2) has a nick, dent, or scratch in an HPC cone shaft aft 
bolt hole that is greater than the serviceable limit.''
    We disagree. The intent of the Installation Prohibition paragraph 
is to mandate the new serviceable limit of 0.002 inch for damage to the 
inner diameter of the bolt holes for the entire GP7270 fleet. Any parts 
with damage beyond this limit may be repaired using the approved 
procedures listed in the engine manual, provided that you include shot 
peening as required by paragraph (f)(2) of this AD. We did not change 
this AD.

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 also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this AD.

Related Service Information Under 1 CFR Part 51

    EA has issued SB No. EAGP7-72-329, dated July 21, 2015 and SB No. 
EAGP7-72-330, dated July 21, 2015. The service information describes 
procedures for shotpeening the HPC forward stubshaft and inspecting the 
HPC forward stubshaft bolt-hole inner diameter respectively. This 
service information is reasonably available because the interested 
parties have access to it through their normal course of business or by 
the means identified in the ADDRESSES section of this final rule.

Costs of Compliance

    We estimate that this AD affects zero engines installed on 
airplanes of U.S. registry. The average labor rate is $85 per hour. 
Based on these figures, we estimate the cost of this AD on U.S. 
operators to be $0.

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:

[[Page 4167]]

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):

2015-28-01 Engine Alliance: Amendment 39-18384; Docket No. FAA-2015-
3585; Directorate Identifier 2015-NE-22-AD.

(a) Effective Date

    This AD is effective March 1, 2016.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Engine Alliance (EA) GP7270 turbofan engines 
with a high-pressure compressor (HPC) cone shaft, part number 382-
100-907-0, installed.

(d) Unsafe Condition

    This AD was prompted by the manufacturer informing us that the 
inspection and repair criteria in the maintenance manual for aft 
bolt holes of the HPC cone shaft on the affected engines is 
incorrect. We are issuing this AD to prevent failure of the HPC cone 
shaft, which could lead to uncontained engine failure and damage to 
the airplane.

(e) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.
    (1) For HPC cone shafts with serial numbers listed in EA Service 
Bulletin (SB) No. EAGP7-72-330, dated July 21, 2015, inspect the 
inner diameter of the HPC cone shaft aft bolt holes for nicks, 
dents, pits, and scratches before accumulating 9,000 cycles since 
new (CSN). Do not reinstall the HPC cone shaft if the aft bolt hole 
has any nicks, dents, pits, or scratches that are greater than 0.002 
inch in depth.
    (2) For HPC cone shafts with serial numbers listed in EA SB No. 
EAGP7-72-329, dated July 21, 2015, shot peen the HPC cone shaft aft 
bolt holes before accumulating 9,000 CSN. Use paragraph 1 of the 
Accomplishment Instructions in EA SB No. EAGP7-72-329 to do the shot 
peening.

(f) Installation Prohibition

    After the effective date of this AD, do not install an HPC cone 
shaft on any engine with the following:
    (1) any nicks, dents, pits, or scratches in an HPC cone shaft 
aft bolt hole that is greater than 0.002 inch in depth; or
    (2) any repair of an HPC cone shaft aft bolt hole that did not 
include shot peening.

(g) Alternative Methods of Compliance (AMOCs)

    The Manager, Engine Certification Office, 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: [email protected].

(h) Related Information

    For more information about this AD, contact Kyle Gustafson, 
Aerospace Engineer, Engine & Propeller Directorate, FAA, 1200 
District Avenue, Burlington, MA 01803; phone: 781-238-7183; fax: 
781-238-7199; email: [email protected].

(i) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Engine Alliance (EA) Service Bulletin (SB) No. EAGP7-72-329, 
dated July 21, 2015.
    (ii) EA SB No. EAGP7-72-330, dated July 21, 2015.
    (3) For EA service information identified in this AD, contact 
Engine Alliance, 400 Main St., East Hartford, CT 06108, M/S 169-10; 
phone: 800-565-0140; email: [email protected]; Internet: 
sp.engineallianceportal.com.
    (4) You may view this service information at FAA, Engine & 
Propeller Directorate, 1200 District Avenue, Burlington, MA. For 
information on the availability of this material at the FAA, call 
781-238-7125.
    (5) You may view this service information at the National 
Archives and Records Administration (NARA). For information on the 
availability of this material at NARA, call 202-741-6030, or go to: 
http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Burlington, Massachusetts, on January 13, 2016.
Gaetano Sciortino,
Acting Directorate Manager, Engine & Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2016-01268 Filed 1-25-16; 8:45 am]
 BILLING CODE 4910-13-P