Document ID: FAA-2011-0392-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: General Electric Co. CT7-8, CT7-8A, CT7-8A1, CT7 8E, and CT7-8F5 Turboshaft Engines
Posted Date: 2011-05-02T04:00Z

[Federal Register Volume 76, Number 84 (Monday, May 2, 2011)]
[Proposed Rules]
[Pages 24407-24408]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-10522]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0392; Directorate Identifier 2011-NE-12-AD]
RIN 2120-AA64

Airworthiness Directives; General Electric Company CT7-8, CT7-8A, 
CT7-8A1, CT7-8E, and CT7-8F5 Turboshaft Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for the 
products listed above. This proposed AD would require the installation 
of an accessory gearbox (AGB) axis-A oil slinger nut to the axis-A 
shaft assembly. This proposed AD was prompted by four reports of 
unrecoverable engine stalls, during hover in a left-roll attitude. We 
are proposing this AD to prevent an unrecoverable engine stall, leading 
to a helicopter forced landing or accident.

DATES: We must receive comments on this proposed AD by June 16, 2011.

ADDRESSES: You may send comments 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 GE-
Aviation, M/D Rm. 285, One Neumann Way, Cincinnati, OH 45215; 
telephone: 513-552-3272; e-mail: geaeaoc@ge.com. You may review copies 
of the referenced 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.

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: Walter Meibaum, Aerospace Engineer, 
Engine & Propeller Directorate, FAA, 12 New England Executive Park, 
Burlington, MA 01803; phone: 781-238-7119; fax: 781-238-7199; e-mail: 
walter.meibaum@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-2011-0392; 
Directorate Identifier 2011-NE-12-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.

[[Page 24408]]

Discussion

    We received four reports of General Electric Company (GE) CT7-8 
series turboshaft helicopter engines experiencing unrecoverable engine 
stalls, during hover in a left-roll attitude. Investigation revealed 
that during a prolonged left roll, excessive return oil from the AGB 
may return to the A-sump and exceed the sump's scavenging capability. 
The sump then floods, leading to over-heated oil, which preheats the 
air entering the engine's compressor. This preheated air causes inlet 
thermal distortion. This condition, if not corrected, could result in 
an unrecoverable engine stall, leading to a helicopter forced landing 
or accident.

Relevant Service Information

    We reviewed GE Aircraft Engines CT7-8 Turboshaft Engine Service 
Bulletin (SB) No. CT7-8 S/B 72-0033, dated February 11, 2011. The SB 
describes procedures for installing the AGB axis-A oil slinger nut to 
the axis-A shaft assembly.

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 engines of the same type design.

Proposed AD Requirements

    This proposed AD would require the installation of an AGB axis-A 
oil slinger nut to the axis-A shaft assembly.

Costs of Compliance

    We estimate that this proposed AD would affect 80 engines installed 
on helicopters of U.S. registry. We also estimate that it would take 
about one work-hour per engine to perform the actions required by this 
proposed AD, and that the average labor rate is $85 per work-hour. 
Required parts would cost about $700 per engine. Based on these 
figures, we estimate the total cost of the proposed AD to U.S. 
operators to be $62,800.

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, 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

    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]

    2. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

General Electric Company: Docket No. FAA-2011-0392; Directorate 
Identifier 2011-NE-12-AD.

Comments Due Date

    (a) We must receive comments by June 16, 2011.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to the following General Electric Company 
(GE) turboshaft engines:
    (1) CT7-8, all engine serial numbers (S/Ns).
    (2) CT7-8A, engine S/Ns 947565 and below.
    (3) CT7-8A1, engine S/Ns 530017 and below.
    (4) CT7-8E, engine S/Ns 953068 and below, and S/Ns 953070 and 
953072.
    (5) CT7-8F5, engine S/Ns 731005 and below, and S/Ns 731007, 
731008, 817021, and 817022.

Unsafe Condition

    (d) This AD was prompted by four reports of unrecoverable engine 
stalls, during hover in a left-roll attitude. We are issuing this AD 
to prevent an unrecoverable engine stall, leading to a helicopter 
forced landing or accident.

Compliance

    (e) Comply with this AD at the next engine shop visit, the next 
1,500-hour helicopter inspection, or before operation after next 
engine installation, whichever occurs first, unless already done.

Installation of Accessory Gearbox (AGB) Axis-A Oil Slinger Nut

    (f) Install the AGB axis-A oil slinger nut to the axis-A shaft 
assembly. Use Accomplishment Instructions, paragraphs 3.A. through 
3.C. of GE Aircraft Engines CT7-8 Turboshaft Engine Service Bulletin 
No. CT7-8 S/B 72-0033, dated February 11, 2011, to do the 
installation.

Alternative Methods of Compliance (AMOCs)

    (g) The Manager, Engine Certification Office, FAA, has the 
authority to approve AMOCs for this AD, if requested using the 
procedures found in 14 CFR 39.19.

Related Information

    (h) For more information about this AD, contact Walter Meibaum, 
Aerospace Engineer, Engine & Propeller Directorate, FAA, 12 New 
England Executive Park, Burlington, MA 01803; phone: 781-238-7119; 
fax: 781-238-7199; e-mail: walter.meibaum@faa.gov.
    (i) For service information identified in this AD, contact GE-
Aviation, M/D Rm. 285, One Neumann Way, Cincinnati, OH 45215; 
telephone: 513-552-3272; e-mail: geaeaoc@ge.com. You may review 
copies of the referenced 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 April 25, 2011.
Peter A. White,
Acting Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-10522 Filed 4-29-11; 8:45 am]
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