[Federal Register Volume 68, Number 26 (Friday, February 7, 2003)]
[Proposed Rules]
[Pages 6379-6380]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-2995]



[[Page 6379]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NE-23-AD]
RIN 2120-AA64


Airworthiness Directives; General Electric CF34-8C1 Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

DATES: Comments must be received by April 8, 2003.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 2002-NE-23-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location, by appointment, between 8 a.m. and 4:30 p.m., Monday 
through Friday, except Federal holidays. Comments may also be sent via 
the Internet using the following address: ``[email protected] ''. 
Comments sent via the Internet must contain the docket number in the 
subject line.

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: 

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications should identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2002-NE-23-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRM's

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 2002-NE-23-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    GE has conducted a refined stress analysis for low-cycle fatigue 
(LCF) life on GE CF34-8C1 combustion chamber assemblies, P/N 
4126T87G04, and has found a new critical location with a lower LCF life 
limit than the currently published life limit. Exceeding the LCF life 
limit could lead to crack initiation and propagation to rupture. This 
condition, if not corrected, could result in rupture of the combustion 
chamber assembly and possible engine fire.

FAA's Determination of an Unsafe Condition and Proposed Actions

    Since an unsafe condition has been identified that is likely to 
exist or develop on other GE CF34-8C1 engines of the same type design, 
the proposed AD would require replacing the combustion chamber 
assembly, P/N 4126T87G04, before accumulating 28,000 cycles-since-new 
(CSN) and prohibit installation of any combustion chamber assembly, P/N 
4126T87G04 that has 28,000 CSN or greater into any engine.

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 proposed 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 prorated cost of lost life of 
9,800 CSN per engine, the total cost of the proposed AD to U.S. 
operators is estimated to be $1,600,000.

Regulatory Analysis

    This proposed 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 proposed rule.
    For the reasons discussed above, I certify that this proposed 
regulation (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 copy of the draft 
regulatory evaluation prepared for this action 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.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 by adding the following new 
airworthiness directive:


[[Page 6380]]


General Electric: 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 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 with 
Sec. Sec.  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.

    Issued in Burlington, Massachusetts, on January 30, 2003.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 03-2995 Filed 2-6-03; 8:45 am]
BILLING CODE 4910-13-P