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

[Federal Register Volume 76, Number 193 (Wednesday, October 5, 2011)]
[Rules and Regulations]
[Pages 61559-61561]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-25654]


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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; 
Amendment 39-16808; AD 2011-19-03]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

DATES: This AD is effective November 9, 2011.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of November 9, 
2011.

ADDRESSES: For service information identified in this AD, contact GE-
Aviation, M/D Rm. 285, One Neumann Way, Cincinnati, OH 45215; phone: 
513-552-3272; e-mail: [email protected]. 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 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: Walter Meibaum, Aerospace Engineer,

[[Page 61560]]

Engine & Propeller Directorate, FAA, 12 New England Executive Park, 
Burlington, MA 01803; phone: 781-238-7119; fax: 781-238-7199; e-mail: 
[email protected].

SUPPLEMENTARY INFORMATION: 

Discussion

    We received four reports of 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. We issued a 
notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include 
an AD that would apply to the specified products. That NPRM published 
in the Federal Register on May 2, 2011 (76 FR 24407). That NPRM 
proposed to require the installation of an AGB axis-A oil slinger nut 
to the axis-A shaft assembly.

Comments

    We gave the public the opportunity to participate in developing 
this AD. We received no comments on the NPRM published in the Federal 
Register on May 2, 2011 (76 FR 24407).
    Since we issued the NPRM published in the Federal Register on May 
2, 2011 (76 FR 24407), GE issued a revision to the service bulletin we 
are incorporating by reference in this AD. The revision includes new 
information in the procedure required to torque the oil slinger nut. 
This AD incorporates by reference, GE Aircraft Engines CT7-8 Turboshaft 
Engine Service Bulletin No. CT7-8 S/B 72-0033, Revision 1, dated April 
28, 2011.
    Also since we issued the NPRM published in the Federal Register on 
May 2, 2011 (76 FR 24407), we discovered that in the applicability 
paragraph, we inadvertently omitted engine serial number 953071. We 
corrected that omission in paragraph (c) (4) by changing ``CT7-8E, 
engine S/Ns 953068 and below, and S/Ns 953070 and 953072'' to ``CT7-8E, 
engine S/Ns 953068 and below, and S/Ns 953070 through 953072''.

Conclusion

    We reviewed the relevant data and determined that air safety and 
the public interest require adopting the AD as proposed except for 
minor editorial changes. We have determined that these minor changes 
are consistent with the intent that was proposed in the NPRM published 
in the Federal Register on May 2, 2011 (76 FR 24407) for correcting the 
unsafe condition.

Costs of Compliance

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

    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
    (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):

2011-19-03 General Electric Company: Amendment 39-16808; Docket No. 
FAA-2011-0392; Directorate Identifier 2011-NE-12-AD.

Effective Date

    (a) This AD is effective November 9, 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 
through 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.

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, Revision 1, dated April 28, 2011, to do the 
installation.

[[Page 61561]]

Previous Credit

    (g) An oil slinger nut installation performed before the 
effective date of this AD using GE Aircraft Engines CT7-8 Turboshaft 
Engine Service Bulletin No. CT7-8 S/B 72-0033, dated February 11, 
2011, satisfies the installation requirements of this AD.

Alternative Methods of Compliance (AMOCs)

    (h) 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

    (i) 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: [email protected].

Material Incorporated by Reference

    (j) You must use the following service information to do the 
actions required by this AD, unless the AD specifies otherwise. The 
Director of the Federal Register approved the incorporation by 
reference (IBR) under 5 U.S.C. 552(a) and 1 CFR part 51 of the 
following service information on the date specified:
    (1) GE Aircraft Engines CT7-8 Turboshaft Engine Service Bulletin 
No. CT7-8 S/B 72-0033, Revision 1, dated April 28, 2011, approved 
for IBR November 9, 2011.
    (2) For service information identified in this AD, contact GE-
Aviation, M/D Rm. 285, One Neumann Way, Cincinnati, OH 45215; phone: 
513-552-3272; e-mail: [email protected].
    (3) You may review copies of the 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.
    (4) You may also review copies of the service information that 
is incorporated by reference at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at an NARA facility, call 202-741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Burlington, Massachusetts, on September 8, 2011.
Peter A. White,
Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-25654 Filed 10-4-11; 8:45 am]
BILLING CODE 4910-13-P

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