[Federal Register Volume 69, Number 157 (Monday, August 16, 2004)]
[Proposed Rules]
[Pages 50344-50345]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-18642]


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DEPARTMENT OF TRANSPORTATION (DOT)

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-18869; Directorate Identifier 2004-NE-23-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for General Electric Company (GE) CF34-3A1 turbofan engines with 
certain high pressure turbine (HPT) rotating components installed. This 
proposed 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. We are proposing this AD to 
clarify that these HPT rotating components have life limits in order to 
prevent low cycle fatigue (LCF) cracking and failure of those 
components, leading to uncontained engine failure and damage to the 
airplane.

DATES: We must receive any comments on this proposed AD by October 15, 
2004.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-001.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    You may examine the comments on this proposed AD in the AD docket 
on the Internet at http://dms.dot.gov.

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:

Docket Management System (DMS)

    We have implemented new procedures for maintaining AD dockets 
electronically. As of May 17, 2004, we posted new AD actions on the DMS 
and assigned a DMS docket number. We track each action and assign a 
corresponding Directorate identifier. The DMS docket No. is in the form 
``Docket No. FAA-200X-XXXXX.'' Each DMS docket also lists the 
Directorate identifier (``Old Docket Number'') as a cross-reference for 
searching purposes.

Comments Invited

    We invite you to submit any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2004-18869; 
Directorate Identifier 2004-NE-23-AD'' in the subject line of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.gov, including any personal information you provide. We will also 
post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of the 
DMS Web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You may review the DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78) or you 
may visit http://dms.gov.
    We are reviewing the writing style we currently use in regulatory 
documents. We are interested in your comments on whether the style of 
this document is clear, and your suggestions to improve the clarity of 
our communications that affect you. You can get more information about 
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.

Examining the AD Docket

    You may examine the docket that contains the proposal, any comments 
received and, any final disposition in person at the DMS 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.

Discussion

    CF34-3A1 engines are used in both business jet and regional jet 
applications. The regional jet is used in both commercial, and 
corporate and private applications. In May of 2003, GE issued a 
Temporary Revision to the CF34 Engine Manual, SEI-756, that removed the 
life limits from the following parts used in the commercial 
application:

 6078T90P01, Balance Piston Air Seal.
 6017T00P05, HPT Rotor Shaft.
 4027T15P03, Stage 1 Front Cooling Plate.

[[Page 50345]]

 6078T93P01 and 6078T93P02, Stage 1 Turbine Disk.
 5041T70P03, Stage 1 Aft Cooling Plate.
 5023T97P03, Stage 2 Rear Cooling Plate.
 6078T94P01 and 6078T94P02, Stage 2 Turbine Disk.
 5042T29P02, Stage 2 Front Cooling Plate.
 5041T67P02, Outer Torque Coupling.
 5079T02P01, Inner Torque Coupling.

As a result of that Temporary Revision removing the life limits of 
these parts from the engine manual, operators may not realize that the 
parts must be removed from service prior to those limits. In March of 
2004, we became aware that a CF34-3A1 lease engine with some or all of 
these part number components installed, was introduced into the 
commercial regional jet fleet. We have since learned that there are a 
total of eight CF34-3A1 lease engines, with some or all of these part 
number components installed, which may be operated in commercial 
regional jets. We are therefore proposing this AD to clarify that these 
parts still have life limits and must be removed from service before 
exceeding those limits.
    This condition, if not corrected, could result in HPT rotating 
components being operated beyond their life limit, which could result 
in LCF cracking and failure of those components, leading to uncontained 
engine failure and damage to the airplane.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. We are proposing this AD, which would clarify 
that the HPT rotating components listed by part number have a life 
limit of 6,000 cycles-since-new.

Costs of Compliance

    We estimate that eight CF34-3A1 turbofan engines installed on 
airplanes of U.S. registry would be affected by this proposed AD. Since 
the life limits for the listed HPT rotating components were contained 
in the original approved type design, and since we estimate that no 
affected engine has a component that is near or approaching that limit, 
we estimate that this AD will not resulting in any additional direct 
labor or part costs.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify that the 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. Would 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 proposal 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.

The Proposed Amendment

    Under the authority delegated to me by the Administrator, the 
Federal Aviation Administration proposes to amend 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. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive:

General Electric Company: Docket No. FAA-2004-18869; Directorate 
Identifier 2004-NE-23-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by October 15, 
2004.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to General Electric Company (GE) CF34-3A1 
turbofan engines with one or more of the high pressure turbine (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.
------------------------------------------------------------------------

These CF34-3A1 turbofan engines are installed on, but not limited 
to, Bombardier series Regional Jet Model CL-600-2B19 (Regional Jet 
Series 100 and 440) airplanes.

Unsafe Condition

    (d) This AD results from the discovery that the manufacture 
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 are issuing this AD to clarify that the HPT 
rotating component part numbers, listed in Table 1 of this AD, have 
a life limit to prevent low cycle fatigue (LCF) cracking and failure 
of those components, leading to 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.

Material Incorporated by Reference

    (h) None.

Related Information

    (i) 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 9, 2004.
Ann Mollica,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 04-18642 Filed 8-13-04; 8:45 am]
BILLING CODE 4910-13-P