Document ID: FAA-2012-1329-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: Engine Alliance Turbofan Engines
Posted Date: 2013-02-07T05:00Z

[Federal Register Volume 78, Number 26 (Thursday, February 7, 2013)]
[Proposed Rules]
[Pages 9003-9005]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-02721]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2012-1329; Directorate Identifier 2012-NE-46-AD]
RIN 2120-AA64

Airworthiness Directives; Engine Alliance 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 
certain Engine Alliance GP7270 and GP7277 turbofan engines. This 
proposed AD was prompted by damage to the high-pressure compressor 
(HPC) stage 7-9 spool caused by failure of the baffle plate feature on 
affected HPC stage 6 disks. This proposed AD would require initial and 
repetitive borescope inspections of the baffle plate feature and 
removal from service of the HPC stage 6 disk before further flight, if 
the plate is missing material. This proposed AD would also require 
mandatory removal from service of these HPC stage 6 disks at the next 
HPC module exposure. We are proposing this AD to prevent uncontained 
failure of the HPC stage 7-9 spool, uncontained engine failure, and 
damage to the airplane.

DATES: We must receive comments on this proposed AD by April 8, 2013.

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.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Engine Alliance, 411 Silver Lane, East Hartford, CT 06118, phone: 800-
565-0140; Web site: https://www.engineallianceportal.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, call 781-238-7125.

[[Page 9004]]

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; 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: Martin Adler, Aerospace Engineer, 
Engine & Propeller Directorate, FAA, 12 New England Executive Park, 
Burlington, MA 01803; phone: 781-238-7157; fax: 781-238-7199; email: 
martin.adler@faa.gov.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2012-1329; 
Directorate Identifier 2012-NE-46-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    We received reports of the baffle plate feature failing on HPC 
stage 6 disks, part number (P/N) 382-100-505-0 from high cycle fatigue. 
The failures resulted in material from the baffle plate feature causing 
damage to the HPC stage 7-9 spool, causing the spool to crack. Engine 
Alliance has introduced a redesigned HPC stage 6 disk with a different 
P/N, to eliminate the failures. This condition, if not corrected, could 
result in uncontained failure of the HPC stage 7-9 spool, uncontained 
engine failure, and damage to the airplane.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

    This proposed AD would require initial and repetitive borescope 
inspections of the HPC stage 6 disk baffle plate feature and removal 
from service of any HPC stage 6 disk, P/N 382-100-505-0, before further 
flight if the feature is missing any material. This proposed AD would 
also require mandatory removal from service of these HPC stage 6 disks 
at the next HPC module exposure, but no later than accumulating 6,800 
cycles-since-new on the disk.

Costs of Compliance

    We estimate that this proposed AD would affect no engines installed 
on airplanes of U.S. registry, and the cost to 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

    We determined 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 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.

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

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):

Engine Alliance: Docket No. FAA-2012-1329; Directorate Identifier 
2012-NE-46-AD.

(a) Comments Due Date

    We must receive comments by April 8, 2013.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Engine Alliance GP7270 and GP7277 turbofan 
engines with a high-pressure compressor (HPC) stage 6 disk, part 
number (P/N) 382-100-505-0, installed.

(d) Unsafe Condition

    This AD was prompted by damage to the HPC stage 7-9 spool caused 
by failure of the baffle plate feature on affected HPC stage 6 
disks. We are issuing this AD to prevent uncontained failure of the 
HPC stage 7-9 spool, uncontained engine failure, and damage to the 
airplane.

(e) Compliance

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

(f) Borescope Inspections

    (1) For HPC stage 6 disks with fewer than 1,000 cycles-since-new 
(CSN) on the effective date of this AD, initially borescope inspect 
the baffle plate feature on the disk (360 degrees) before 
accumulating 1,500 CSN.
    (2) For HPC stage 6 disks with 1,000 CSN or more on the 
effective date of this AD, initially borescope inspect the baffle 
plate feature on the disk (360 degrees) within the next 500 cycles-
in-service (CIS).

[[Page 9005]]

    (3) Thereafter, repetitively borescope inspect the baffle plate 
feature on the disk (360 degrees) within every 500 CIS.
    (4) Remove the HPC stage 6 disk before further flight if found 
cracked or with missing material.

(g) Mandatory Removal From Service of Affected HPC Stage 6 Disks

    At next HPC module exposure, but not to exceed 6,800 CSN on the 
HPC stage 6 disk, remove the HPC stage 6 disk, P/N 382-100-505-0, 
from service.

(h) Installation Prohibition

    After the effective date of this AD, do not install any HPC 
stage 6 disk, P/N 382-100-505-0, into any HPC module.

(i) Definition

    For the purpose of this AD, HPC module exposure is defined as 
separation of the flanges between the compressor case and the 
combustion diffuser case.

(j) 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.

(k) Related Information

    (1) For more information about this AD, contact Martin Adler, 
Aerospace Engineer, Engine & Propeller Directorate, FAA, 12 New 
England Executive Park, Burlington, MA 01803; phone: 781-238-7157; 
fax: 781-238-7199; email: martin.adler@faa.gov.
    (2) Engine Alliance Service Bulletin No. EAGP7-72-236, pertains 
to the subject of this AD.
    (3) For service information identified in this AD, contact 
Engine Alliance, 411 Silver Lane, East Hartford, CT 06118, phone: 
800-565-0140; Web site: https://www.engineallianceportal.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, call 
781-238-7125.

    Issued in Burlington, Massachusetts, on January 28, 2013.
Robert J. Ganley,
Acting Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-02721 Filed 2-6-13; 8:45 am]
BILLING CODE 4910-13-P