Airworthiness Directives; GE Aircraft Engines CT7 Series Turboprop Engines

[Federal Register Volume 67, Number 5 (Tuesday, January 8, 2002)]
[Rules and Regulations]
[Pages 815-816]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-302]



[[Page 815]]

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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NE-61-AD; Amendment 39-12594; AD 2002-01-03]
RIN 2120-AA64


Airworthiness Directives; GE Aircraft Engines CT7 Series 
Turboprop Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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

SUMMARY: This amendment adopts a new airworthiness directive (AD), that 
is applicable to GE Aircraft Engines (GE) CT7 series turboprop engines. 
This amendment requires removal of stage 2 turbine aft cooling plates 
of a certain part number (P/N) and installation of cooling plates of a 
new design. This amendment is prompted by a report of a stage 2 turbine 
aft cooling plate cracking, resulting in an uncontained engine failure. 
The actions specified by this AD are intended to prevent stage 2 
turbine aft cooling plate cracking, which could result in uncontained 
engine failure, and damage to the airplane.

DATES: Effective date February 12, 2002.

FOR FURTHER INFORMATION CONTACT: Barbara Caufield, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone: (781) 
238-7146; fax: (781) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an AD that is 
applicable to GE Aircraft Engines (GE) CT7 series turboprop engines was 
published in the Federal Register on May 2, 2001 (66 FR 21898). That 
action proposed to require removal of stage 2 turbine aft cooling 
plates of a certain part number (P/N) and installation of cooling 
plates of a new design.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter suggests that the Economic Analysis paragraph be 
changed to reflect that not all cooling plates may be installed in 
engines, and, therefore, while there may be 564 cooling plates 
available worldwide, there are not 564 engines that will be affected by 
the AD. The FAA agrees. Not all cooling plates of the affected design 
are assembled into engines. GE estimates that only 288 affected cooling 
plates have been assembled into engines. Therefore, the Economic 
Analysis statement is changed to reflect that only 288 engines 
worldwide will be affected. The FAA's estimate for engines of the 
number of engines installed on airplanes of US registry, however, 
remains the same.
    The manufacturer asks that paragraph (a) and (b) of the Compliance 
Section be changed by adding serial number prefix GFF to Stage 2 aft 
cooling plate P/N 6064T07P02. The FAA agrees, because only cooling 
plates with serial number prefix GFF are affected. The FAA has limited 
the applicabilty of this AD to just those cooling plates, P/N 
6064T07P02 with serial numbers that begin with the letters ``GFF.'' In 
addition, paragraphs (a) and (b) have been changed accordingly.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Economic Analysis

    There are approximately 288 engines of the affected design in the 
worldwide fleet. The FAA estimates that 180 engines installed on 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 0.5 work hour per engine to accomplish the 
proposed actions, and that the average labor rate is $60 per work hour. 
Required aft cooling plates would cost approximately $15,282 per 
engine. Based on these figures, the total cost impact of the proposed 
AD on U.S. operators is estimated to be $2,756,160. The manufacturer 
has stated that it may provide the new design aft cooling plate at no 
cost to operators, and that if the aft cooling plate is replaced at the 
next engine or hot section module overhaul shop visit, no additional 
labor costs will be incurred.

Regulatory Analysis

    This final rule does not have federalism implications, as defined 
in Executive Order 13132, because it 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. Accordingly, 
the FAA has not consulted with state authorities prior to publication 
of this final rule.
    For the reasons discussed above, I certify that this action (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); and (3) if promulgated, 
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. A final evaluation has been prepared for 
this action and it is contained in the Rules Docket. A copy of it may 
be obtained by contacting the Rules Docket at the location provided 
under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (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. Section 39.13 is amended adding a new airworthiness directive to 
read as follows:

2002-01-03  GE Aircraft Engines: Amendment 39-12594. Docket 2000-NE-
61-AD.
    Applicability: This airworthiness directive (AD) is applicable 
to GE Aircraft Engines (GE) CT7 Models CT7-5A2, -5A3, -7A, and -7A1 
turboprop engines with part number (P/N) 6064T07P02 stage 2 aft 
cooling plates with serial numbers beginning with the letters GFF, 
installed on but not limited to Construcciones Aeronauticas, SA CN-
235 series and SAAB Aircraft AB SF340 series airplanes.

    Note 1: This AD applies to each engine identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For engines that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (c) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or

[[Page 816]]

repair on the unsafe condition addressed by this AD; and, if the 
unsafe condition has not been eliminated, the request should include 
specific proposed actions to address it.

    Compliance: Compliance is required at the next overhaul of the 
engine or hot section module, or within 8,000 cycles after the 
effective date of this AD, whichever occurs first, unless already 
done.
    To prevent stage 2 turbine aft cooling plate cracking, which 
could result in uncontained engine failure, and damage to the 
airplane, do the following:
    (a) Replace stage 2 aft cooling plates P/N 6064T07P02 with 
serial numbers that begin with the letters GFF with stage 2 aft 
cooling plate P/N 6064T07P05.
    (b) After the effective date of this AD, do not install any 
stage 2 aft cooling plates P/N 6064T07P02 with serial numbers that 
begin with the letters GFF.

Alternative Methods of Compliance

    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Engine Certification Office (ECO). 
Operators must submit their request through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, ECO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the ECO.

Special Flight Permits

    (d) Special flight permits may be issued in accordance 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the airplane to a location where the 
requirements of this AD can be done.

Effective Date

    (e) This amendment becomes effective on February 12, 2002.

    Issued in Burlington, Massachusetts, on December 31, 2001.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 02-302 Filed 1-7-02; 8:45 am]
BILLING CODE 4910-13-P

The complete text was extracted from the official GovInfo HTML edition for this publication. Acquired 2026-10-09T04:23:27.329233+00:00. Text extraction preserves the recorded source wording; it does not determine current requirements.

Open the captured official edition

Source SHA-256

bb23b50c24518927dc499085409e5ada6bba405ac19903c25b7308d3b8bec52f

Text SHA-256

ecc4d14b6d335244b31e62a10acc65cb64d303cf40808523a5cf2ff7d36a8a56