Airworthiness Directives; General Electric Company (GE) CT7-8A Turboshaft Engines

[Federal Register Volume 73, Number 246 (Monday, December 22, 2008)]
[Rules and Regulations]
[Pages 78175-78178]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-29722]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-24261; Directorate Identifier 2006-NE-12-AD; 
Amendment 39-15768; AD 2008-26-02]
RIN 2120-AA64


Airworthiness Directives; General Electric Company (GE) CT7-8A 
Turboshaft Engines

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is superseding an existing airworthiness directive 
(AD) for certain GE CT7-8A turboshaft engines. That AD currently 
requires initial and repetitive inspections of the electrical chip 
detectors for the No. 3 bearing. This AD requires removing from service 
certain GE CT7-8A turboshaft engines within 6,200 cycles-since-new. 
This AD results from investigation for the root causes of two failures 
of the No. 3 bearing. We are issuing this AD to prevent failure of the 
No. 3 bearing due to contamination by aluminum oxide, which could 
result in a possible in-flight shutdown of the engines and loss of 
control or forced landing of the aircraft.

DATES: This AD becomes effective January 26, 2009.

ADDRESSES: You can get the service information identified in this AD 
from General Electric Aircraft Engines CT7 Series Turboshaft Engines, 
1000 Western Ave., Lynn, MA 01910; telephone (781) 594-6726; fax (781) 
594-1583.
    The Docket Operations office is located at Docket Management 
Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, 
SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-
0001.

FOR FURTHER INFORMATION CONTACT: Christopher Richards, Aerospace 
Engineer, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803; e-
mail: [email protected]; telephone (731) 238-7133; fax 
(781) 238-7199.

SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39 by 
superseding AD 2006-06-51, Amendment 39-14566 (71 FR 19627, April 17, 
2006), with a proposed AD. The proposed AD applies to certain GE CT7-8A 
turboshaft engines. We published the proposed AD in the Federal 
Register on March 19, 2008 (73 FR 14731). That action proposed to:
    <bullet> Delete the requirements to inspect the electrical chip 
detector, and
    <bullet> Require removing any engine that has a serial number (SN) 
listed in Table

[[Page 78176]]

1 of the proposed AD within 6,200 cycles-since-new (CSN) unless the 
front frame was flushed and the No. 3 bearing replaced, and
    <bullet> Prohibit installing any engine that has a SN listed in 
Table 1 of the proposed AD unless the front frame was flushed and the 
No. 3 bearing replaced.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Operations office 
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 street address for 
the Docket Operations office (telephone (800) 647-5527) is provided in 
the ADDRESSES section. Comments will be available in the AD docket 
shortly after receipt.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received.

Request for Changes to Contact Information for Service Information

    One commenter, GE, asks that we change a typographical error in the 
contact information for the service information from Turboprop to 
Turboshaft. They also inform us they changed the contact telephone and 
fax numbers.
    We agree. We changed Turboprop to Turboshaft, and we changed the 
contact telephone and fax numbers to (781) 594-6726 and (781) 594-1583 
respectively.

Request for Changes to Actions Since AD 2006-06-51 Was Issued

    The same commenter asks us to change the second bulleted item in 
Actions Since AD 2006-06-51 Was Issued section and to delete the third 
bulleted item.
    We partially agree. Adding ``within 6,200 cycles-since-new (CSN) 
unless * * * replaced'' is more clear. However, that section appears in 
the preamble of the NPRM only. The final rule doesn't contain that 
section so we can't make the requested change to the preamble.

Request To Remove the Prohibition Against Installing Engines After the 
Effective Date of This AD

    The same commenter asks us to remove the paragraph prohibiting 
reinstallation of an engine until this AD has been complied with. The 
commenter states there should be no restriction on reinstalling an 
engine already in the field that might have been temporarily removed 
for maintenance or used as a spare engine. The commenter states when 
these engines are sent to an Engine Overhaul Shop (within 6,200 CSN) 
they will get their front frame flushed and No. 3 bearing replaced. 
Therefore, within the 6,200 CSN compliance requirement, there should be 
no restriction to reinstalling the engines listed in Table 1 of the 
proposed AD.
    We agree. We have deleted the installation prohibition from the 
regulatory text of the final rule.

Request To Reference the Latest Revision of Service Bulletin CT7-8 S/B 
72-0017

    The same commenter asks us to change the Relevant Service 
Information section and the Related Information paragraph to include 
Service Bulletin (SB) CT7-8 S/B 72-0017, Revision 01, dated February 
15, 2008, and SB CT7-8 S/B 72-0017, Revision 02, dated May 14, 2008. 
The commenter states that GE issued SB CT7-8 S/B 72-0017, Revision 01, 
dated February 15, 2008, and SB CT7-8 S/B 72-0017, Revision 02, dated 
May 14, 2008, after we issued the NPRM.
    We partially agree. We added SB CT7-8 S/B 72-0017, Revision 02, 
dated May 14, 2008, to the Related Information paragraph (i) and 
changed paragraph (g) to state ``remove the engine from service and 
flush the front frame and replace the No. 3 bearing. GE Aircraft 
Engines Service Bulletin No. CT7-8 S/B 72-0017, Revision 02, dated May 
14, 2008 or earlier revision, contains information on flushing the 
front frame and replacing the No. 3 bearing.'' However, the Relevant 
Service Information section appears in the preamble of the NPRM only. 
The final rule doesn't contain that section so we can't make the 
requested change to the preamble.

Request To Add Compliance Times to the Related Service Information 
Paragraph

    The same commenter asks us to change the Related Service 
Information paragraph to include the compliance time of ``within 6,200 
CSN or at the next shop visit, whichever occurs first.'' The commenter 
recommends inserting this information to provide a brief explanation of 
the intent of GE CT7-8 Service Bulletin 72-0017.
    We don't agree. We already specify the compliance times in the 
regulatory text. The purpose of the Related Service Information 
paragraph is to provide a user with additional information that they 
can use when complying with the regulatory requirements of the AD.

Request To Remove an Engine SN From Table 1 of the AD

    The same commenter asks us to remove engine SN 947266 from Table 1 
of the AD. The commenter states that they added that engine to the 
``completed compliance list'' in Revision 01 of GE Aircraft Engines 
CT7-8 Service Bulletin 72-0017.
    We agree. We removed engine SN 947266 from Table 1 of the AD.

Request To Replace the Phrase ``Remove the Engine From Service''

    The same commenter asks us to replace the phrase ``remove the 
engine from service'' in paragraph (g) with ``Comply with GE Aircraft 
Engines CT7-8 Service Bulletin 72-0017 Rev 00 or Rev 01 or Rev 02, 
unless the front frame was flushed and the No. 3 bearing was replaced 
previously.'' The commenter recommends the change to clarify the 
requirements by stating that each engine listed in Table 1 of the AD 
must comply with the requirements of GE Aircraft Engines CT7-8 Service 
Bulletin 72-0017 within 6,200 CSN.
    We partially agree. We determined paragraph (g) is clear because it 
states the actions apply to engines with SNs listed in Table 1 and 
because paragraph (e) requires performing the actions unless the 
actions have already been done. However, we did change paragraph (g) 
from ``within 6,200 cycles-since new, remove engine from service'' to 
``within 6,200 cycles-since new, remove the engine from service and 
flush the front frame and replace the No. 3 bearing. GE CT7-8 Shop 
Manual, GEK 10517, and GE Aircraft Engines Service Bulletin No. CT7-8 
S/B 72-0017, Revision 02, dated May 14, 2008, or earlier revision, 
contain information on flushing the front frame and replacing the No. 3 
bearing.'' We also added a new paragraph (h) to prohibit installing any 
No. 3 bearing removed as required by paragraph (g).

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
We have determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    We estimate that this AD will affect 29 engines installed on 
helicopters of U.S. registry. We also estimate that it

[[Page 78177]]

will take about 66.0 work-hours per engine to perform the required 
actions, and that the average labor rate is $80 per work-hour. Required 
parts will cost about $3,476 per engine. Based on these figures, we 
estimate the total cost of the AD to U.S. operators to be $253,924.

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 have determined that 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); and
    (3) 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.
    We prepared a summary of the costs to comply with this AD and 
placed it in the AD Docket. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the Federal Aviation Administration 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 removing Amendment 39-14566 (71 FR 
19627, April 17, 2006) and by adding a new airworthiness directive, 
Amendment 39-15768, to read as follows:

2008-26-02 General Electric Company: Amendment 39-15768. Docket No. 
FAA-2006-24261; Directorate Identifier 2006-NE-12-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective January 
26, 2009.

Affected ADs

    (b) This AD supersedes AD 2006-06-51, Amendment 39-14566.

Applicability

    (c) This AD applies to General Electric Company (GE) CT7-8A 
turboshaft engines that have a serial number (SN) listed in Table 1 
of this AD. These engines are installed on, but not limited to, 
Sikorsky S92 helicopters.

               Table 1--Affected Engines by Serial Number
------------------------------------------------------------------------
 
------------------------------------------------------------------------
                          Engine Serial Number
------------------------------------------------------------------------
947205       947215       947230      947243      947254      947265
947206       947217       947232      947244      947255      947274
947207       947218       947233      947245      947256      947277
947208       947219       947235      947247      947258      947278
947209       947220       947238      947248      947260      947279
947210       947221       947240      947249      947261      947280
947211       947223       947241      947250      947262      947284
947212       947225       947242      947253      947263      947285
947214       947228
------------------------------------------------------------------------

Unsafe Condition

    (d) This AD results from investigation for the root causes of 
two failures of the No. 3 bearing. We are issuing this AD to prevent 
failure of the No. 3 bearing due to contamination by aluminum oxide, 
which could result in a possible in-flight shutdown of the engines 
and loss of control or forced landing of the aircraft.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified unless the 
actions have already been done.
    (f) No further action is required if:
    (1) Your engine has a SN that is not listed in Table 1 of this 
AD, or
    (2) Your engine has a SN listed in Table 1 of this AD, but the 
engine log specifies that the front frame was flushed and the No. 3 
bearing was replaced.

Engines With SNs listed in Table 1 of This AD

    (g) For engines with a SN listed in Table 1 of this AD, within 
6,200 cycles-since-new, remove the engine from service and flush the 
front frame and replace the No. 3 bearing. GE CT7-8 Shop Manual, GEK 
10517, contains information on replacing the No. 3 bearing and GE 
Aircraft Engines Service Bulletin No. CT7-8 S/B 72-0017, Revision 
02, dated May 14, 2008, or earlier revision, contains information on 
flushing the front frame and replacing the No. 3 bearing.

Prohibition Against Reinstalling a No. 3 Bearing

    (h) After the effective date of this AD, do not install any No. 
3 bearing removed as a requirement of paragraph (g) of this AD.

Alternative Methods of Compliance

    (i) The Manager, Engine Certification Office, FAA, has the 
authority to approve alternative methods of compliance for this AD 
if requested using the procedures found in 14 CFR 39.19.

Related Information

    (j) GE CT7-8 Shop Manual, GEK 10517, and GE Aircraft Engines 
Service Bulletin No. CT7-8 S/B 72-0017, Revision 02, dated May 14, 
2008 and earlier revisions pertain to the subject of this AD. 
Contact General Electric Aircraft Engines CT7 Series Turboshaft

[[Page 78178]]

Engines, 1000 Western Ave., Lynn, MA 01910; telephone (781) 594-
6726; fax (781) 594-1583, for a copy of this service information.
    (k) Contact Christopher Richards, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; telephone (731) 238-7133; fax (781) 
238-7199, for more information about this AD.

Material Incorporated by Reference

    (l) None.

    Issued in Burlington, Massachusetts, on December 9, 2008.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E8-29722 Filed 12-19-08; 8:45 am]
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