Airworthiness Directives; General Electric Company CF34 Series Turbofan Engines

[Federal Register Volume 62, Number 58 (Wednesday, March 26, 1997)]
[Rules and Regulations]
[Pages 14287-14288]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-7597]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-ANE-41; Amendment 39-9972; AD 97-06-15]
RIN 2120-AA64


Airworthiness Directives; General Electric Company CF34 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to General Electric Company CF34 series turbofan engines, 
that reduces the allowable operating cyclic life limit for affected 
high pressure compressor (HPC) stage 1 rotor disks. This amendment is 
prompted by an updated stress and life analysis. The actions specified 
by this AD are intended to prevent HPC stage 1 rotor disk rupture, 
engine failure, and damage to the aircraft.

DATES: Effective May 27, 1997.

FOR FURTHER INFORMATION CONTACT: Eugene Triozzi, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7148, fax (617) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to General Electric Company (GE) CF34 
series turbofan engines was published in the Federal Register on 
December 18, 1995, (60 FR 65035). That action proposed to reduce the 
allowable operating cyclic life limit for affected high pressure 
compressor (HPC) stage 1 rotor disks.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were received on the 
proposal or the FAA's determination of the cost to the public. The FAA 
has determined that air safety and the public interest require the 
adoption of the rule as proposed.

[[Page 14288]]

    There are approximately 440 engines of the affected design in the 
worldwide fleet. The FAA estimates that 150 engines installed on 
aircraft of U.S. registry will be affected by this AD, and that it will 
take approximately zero additional work hours per engine to accomplish 
the required actions. Required parts will cost approximately $7,667 per 
engine, based on the estimated current part cost, prorated downward by 
a factor equal to the quotient of the difference between the original 
cyclic life limit (9,000 cycles) and the revised cyclic life limit 
(6,000 cycles) divided by the original cyclic life limit. Based on 
these figures, the total cost impact of the AD on U.S. operators is 
estimated to be $1,150,000.
    The regulations adopted herein will not have substantial direct 
effects 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. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    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 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. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air Transportation, Aircraft, Aviation safety, Incorporation by 
reference, 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 USC 106(g), 40113, 44701.

Sec. 39.13   [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

97-06-15  General Electric Company: Amendment 39-9972. Docket 95-
ANE-41.

    Applicability: General Electric Company (GE) Models CF34-1A, -
3A, and -3A2 turbofan engines, with high pressure compressor (HPC) 
stage 1 rotor disks, part number 6040T79G01, installed. These 
engines are installed on but not limited to Canadair Limited Model 
CL-600-2A12 and CL-600-2B16 aircraft.

    Note 1: This airworthiness directive (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 (b) of this AD. The request should include an assessment 
of the effect of the modification, alteration, or 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: Required as indicated, unless accomplished 
previously.
    To prevent HPC stage 1 rotor disk rupture, engine failure, and 
damage to the aircraft, accomplish the following:
    (a) Remove from service HPC stage 1 rotor disks prior to 
accumulating 6,000 cycles in service since new, and replace with a 
serviceable part.
    (b) 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. The 
request should be forwarded through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Engine Certification Office.

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

    (c) This amendment becomes effective on May 27, 1997.

    Issued in Burlington, Massachusetts, on March 14, 1997.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 97-7597 Filed 3-25-97; 8:45 am]
BILLING CODE 4910-13-U

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