Airworthiness Directives; General Electric Company CF34-3A1 Turbofan Engines

[Federal Register Volume 70, Number 173 (Thursday, September 8, 2005)]
[Rules and Regulations]
[Pages 53295-53296]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-17761]



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Federal Register / Vol. 70, No. 173 / Thursday, September 8, 2005 / 
Rules and Regulations

[[Page 53295]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-18869; Directorate Identifier 2004-NE-23-AD; 
Amendment 39-14256; AD 2005-18-16]
RIN 2120-AA64


Airworthiness Directives; General Electric Company CF34-3A1 
Turbofan Engines

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

ACTION: Final rule.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
General Electric Company (GE) CF34-3A1 turbofan engines installed on 
Bombardier series Regional Jets with certain high pressure turbine 
(HPT) rotating components installed. This AD requires removal from 
service of certain HPT components prior to the parts exceeding their 
designated life limits. This AD results from the discovery that the 
manufacturer removed certain part numbers of HPT rotating components 
from the Life Limits section of the CF34 Engine Manual, SEI-756. The 
effect of this manual change was the removal of life limits from 
certain components that are eligible for installation in GE CF34-3A1 
engines. We are issuing this AD to impose life limits on these HPT 
rotating components to prevent low cycle fatigue (LCF) cracking and 
failure of those components, which could result in uncontained engine 
failure and damage to the airplane.

DATES: This AD becomes effective October 13, 2005.

ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov or in Room PL-401 on the plaza level of the Nassif 
Building, 400 Seventh Street, SW., Washington, DC.

FOR FURTHER INFORMATION CONTACT: Robert Grant, Aerospace Engineer, 
Engine Certification Office, FAA, Engine & Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7757; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39 
with a proposed airworthiness directive. The proposed AD applies to GE 
CF34-3A1 turbofan engines with certain HPT rotating components 
installed. We published the proposed AD in the Federal Register on 
August 16, 2004 (69 FR 50344). That action proposed a requirement for 
removal from service of certain HPT components prior to their exceeding 
designated life limits.

Examining the AD Docket

    You may examine the docket that contains the AD, any comments 
received, and any final disposition in person at the Docket Management 
Facility Docket Offices between 9 a.m. and 5 p.m., Monday through 
Friday, except Federal holidays. The Docket Office (telephone (800) 
647-5227) is located on the plaza level of the Department of 
Transportation Nassif Building at the street address stated in 
ADDRESSES. Comments will be available in the AD docket shortly after 
the DMS receives them.

Comments

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

Identify Affected Engines

    One commenter states that the AD should identify the specific 
engines to which it applies or identify the applicable engines by the 
maintenance manual used. We agree that applicability should be 
clarified. We have reworded the AD to indicate that it applies only to 
CF34-3A1 engines installed on Bombardier series Regional Jet Model CL-
600-2B19 (Regional Jet Series 100 and 440) airplanes with one or more 
of certain HPT rotating components installed.

Challenger Aircraft Not Affected

    Another commenter states that a note should be added to the AD 
indicating that this AD does not apply to CF34-3A1 engines installed on 
Challenger aircraft. We agree. We have clarified this AD to indicate 
that it applies only to engines installed on Bombardier series Regional 
Jet Model CL-600-2B19 (Regional Jet Series 100 and 440) airplanes with 
one or more of certain HPT rotating components installed.

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 would affect eight CF34-3A1 turbofan 
engines installed on airplanes of U.S. registry. We estimate that no 
affected engine has a listed HPT rotating component near its original 
type design life limit. Therefore, we estimate that this AD will not 
result in any additional direct labor or part costs.

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

[[Page 53296]]

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 adding the following new airworthiness 
directive:

2005-18-16 General Electric Company: Amendment 39-14256. Docket No. 
FAA-2004-18869; Directorate Identifier 2004-NE-23-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective October 
13, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to General Electric CF34-3A1 turbofan 
engines installed on Bombardier series Regional Jet Model CL-600-
2B19 (Regional Jet Series 100 and 440) airplanes with one or more of 
the HPT rotating components installed, listed in the following Table 
1:

       Table 1.--HPT Rotating Components With Life Limits Restored
------------------------------------------------------------------------
                Part No.                           Nomenclature
------------------------------------------------------------------------
6078T90P01.............................  Seal, Balance Piston Air.
6017T00P05.............................  Shaft, HPT Rotor.
4027T15P03.............................  Plate, Stage 1 Front Cooling.
6078T93P01.............................  Disk, Stage 1 Turbine.
6078T93P02.............................  Disk, Stage 1 Turbine.
5041T70P03.............................  Plate, Stage 1 Aft Cooling.
5023T97P03.............................  Plate, Stage 2 Rear Cooling.
6078T94P01.............................  Disk, Stage 2 Turbine.
6078T94P02.............................  Disk, Stage 2 Turbine.
5042T29P02.............................  Plate, Stage 2 Front Cooling.
5041T67P02.............................  Coupling, Outer Torque.
5079T02P01.............................  Coupling, Inner Torque.
------------------------------------------------------------------------

Unsafe Condition

    (d) This AD results from the discovery that the manufacturer 
removed the HPT rotating component part numbers, listed in Table 1 
of this AD, from the HPT Life Limits section of the CF34 Engine 
Manual, SEI-756. We view this as a change to the life limit of the 
part, removing the type design life limit and imposing an unlimited 
life on the part. We are issuing this AD to re-impose life limits on 
the HPT rotating components with part numbers listed in Table 1 of 
this AD to prevent LCF cracking and failure of those components, 
which could result in uncontained engine failure and damage to the 
airplane.

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) Remove from service the HPT rotating components listed in 
Table 1 of this AD before exceeding the life limit of 6,000 cycles-
since-new.

Alternative Methods of Compliance

    (g) The Manager, Engine Certification Office, 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

    (h) GE Temporary Revision No. 05-0073, and Temporary Revision 
No. 05-0074, for CF34 Engine Manual, SEI-756, also pertain to the 
subject of this AD.

    Issued in Burlington, Massachusetts, on August 31, 2005.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 05-17761 Filed 9-7-05; 8:45 am]
BILLING CODE 4910-13-P

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