Airworthiness Directives; General Electric CF34-8C1 Turbofan Engines

[Federal Register Volume 68, Number 89 (Thursday, May 8, 2003)]
[Rules and Regulations]
[Pages 24614-24615]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-11266]



[[Page 24614]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NE-23-AD; Amendment 39-13143; AD 2003-09-14]
RIN 2120-AA64


Airworthiness Directives; General Electric CF34-8C1 Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), that 
is applicable to General Electric (GE) CF34-8C1 turbofan engines. This 
amendment requires replacing combustion chamber assemblies, part number 
(P/N) 4126T87G04, before accumulating a new reduced cyclic life limit. 
This amendment is prompted by stress and life analysis conducted by GE. 
The actions specified by this AD are intended to prevent rupture of the 
combustion chamber assembly and possible engine fire.

DATES: Effective June 12, 2003.

ADDRESSES: Information regarding this action may be examined, by 
appointment, at the Federal Aviation Administration (FAA), New England 
Region, Office of the Regional Counsel, 12 New England Executive Park, 
Burlington, MA.

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 (781) 
238-7148; 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 CF34-8C1 turbofan engines was published in the Federal 
Register on February 7, 2003, (68 FR 6379). That action proposed to 
require replacing combustion chamber assemblies, P/N 4126T87G04, before 
accumulating a new reduced cyclic life limit.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comment received.
    One commenter requests that the combustion chamber assembly life be 
reduced to 25,800 cycles-since-new (CSN) from the proposed 28,000 CSN. 
The commenter states that this limit is specified in the GE CF34-8C1 
Engine Maintenance Manual life limits section.
    The FAA does not agree. The 28,000 life limit is the correct life 
limit approved by the FAA for combustion chamber assembly, P/N 
4126T87G04. The GE manual incorrectly lists the lower life limit. That 
limit was submitted by GE for FAA approval in December, 2001. 
Subsequently, GE submitted a request to amend the cycle life limit to 
28,000 CSN and the FAA approved it in March, 2002.
    After careful review of the available data, including the comment 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed. 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 115 GE CF34-8C1 turbofan engines of the 
affected design in the worldwide fleet. The FAA estimates that 75 
engines are installed on airplanes of U.S. registry. The FAA also 
estimates that it would take approximately 24 work hours per engine to 
perform the actions, and that the average labor rate is $60 per work 
hour. Required parts would cost approximately $75,000 per engine. Based 
on these figures and the cost of lost life of 9,800 cycles-since-new 
per engine, the total cost of the AD to U.S. operators is estimated to 
be $1,600,000.

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) 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

0
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

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. Section 39.13 is amended by adding a new airworthiness directive to 
read as follows:

2003-09-14 General Electric: Amendment 39-13143. Docket No. 2002-NE-
23-AD.

    Applicability: This airworthiness directive (AD) is applicable 
to General Electric (GE) CF34-8C1 turbofan engines with combustion 
chamber assembly, part number (P/N) 4126T87G04, installed. These 
engines are installed on, but not limited to Bombardier Inc. Model 
CL-600-2C10 (CRJ-700 & 701) 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 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 with this AD is required as indicated, 
unless already done.
    To prevent rupture of the combustion chamber assembly and 
possible engine fire, do the following:
    (a) Replace combustion chamber assembly, P/N 4126T87G04, at or 
before the combustion chamber assembly accumulates 28,000 cycles-
since-new (CSN).
    (b) After the effective date of this AD, do not install any 
combustion chamber assembly, P/N 4126T87G04, that exceeds 28,000 
CSN.

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

[[Page 24615]]

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.

Effective Date

    (d) This amendment becomes effective on June 12, 2003.

    Issued in Burlington, Massachusetts, on May 1, 2003.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, , Aircraft 
Certification Service.
[FR Doc. 03-11266 Filed 5-7-03; 8:45 am]
BILLING CODE 4910-13-P

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