That AD was the result of a report of a stage 5 LPT disk that failed due to cracking from lowcyclefatigue (LCF) during factory testing. That condition, if not corrected, could result in uncontained engine failure.

Actions Since AD 20041503 Was Issued

Since that AD was issued, we discovered that we published an incorrect part number (P/N) of 6089T89P01 for stage 6 LPT disks. This AD revision corrects that P/N to 6078T89P01. Also, since that AD was issued, we determined that credit for actions completed per previous releases of Alert Service Bulletin CF34AL S/B 72A0173 need to be allowed. This AD revision adds a paragraph in the compliance section to allow that credit.

Relevant Service Information

We have reviewed and approved the technical contents of GE Alert Service Bulletin No. CF34AL S/B 72A0173, Revision 3, dated July 20, 2004, that lists applicable disks by SN, and describes the procedures for performing visual and eddy current inspections on the applicable stage 5 LPT disks and stage 6 LPT disks.

FAA's Determination and Requirements of This AD

The unsafe condition described previously is likely to exist or develop on other GE CF343A1 and 3B1 series turbofan engines of the same type design. We are issuing this AD to prevent LCF failure of stage 5 LPT disks and stage 6 LPT disks, which could lead to uncontained engine failure. This AD requires:

FAA's Determination of the Effective Date

Since an unsafe condition exists that requires the immediate adoption of this AD, we have found that notice and opportunity for public comment before issuing this AD are impracticable, and that good cause exists for making this amendment effective in less than 30 days. 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. FAA200XXXXXX.'' Each DMS docket also lists the Directorate identifier (``Old Docket Number'') as a crossreference for searching purposes.

Comments Invited

This AD is a final rule that involves requirements affecting flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any written relevant data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include ``AD Docket No. FAA200418648; Directorate Identifier 2004NE26AD'' in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify it.

We will post all comments we receive, without change, to http://dms.dot.gov , including any personal information you provide. We will
also post a report summarizing each substantive verbal contact with FAA personnel concerning this 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 1947778) or you may visit http://dms.dot.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 with you. You can get more information about plain language at http://www.plainlanguage.gov.Examining the AD Docket

You may examine the docket that contains the AD, 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
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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. 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 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 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. 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, Incorporation by reference.
Adoption of the Amendment
Under 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 39AIRWORTHINESS 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 removing Amendment 3913737 (69 FR 45562; July 30, 2004), and by adding a new airworthiness directive, Amendment 3913773, to read as follows:
20041503R1 General Electric Company: Amendment 3913773. Docket No. FAA200418648; Directorate Identifier 2004NE26AD.
Effective Date
(a) This airworthiness directive (AD) becomes effective August 31, 2004.
Affected ADs
(b) This AD revises AD 20041503, Amendment 3913737.
Applicability
(c) This AD applies to General Electric Company (GE) CF343A1 and 3B1 series turbofan engines with stage 5 low pressure turbine (LPT) disks, part number (P/N) 6078T92P01, and or stage 6 LPT disks, P/N 6078T89P01, with serial numbers (SNs) listed in Figure 3 of GE Alert Service Bulletin (ASB) No. CF34AL S/B 72A0173, Revision 3, dated July 20, 2004. These engines are installed on, but not limited to, Bombardier Canadair CL6002B19 (RJ) airplanes.
Unsafe Condition
(d) This AD results from a report of a stage 5 LPT disk that failed due to cracking from lowcyclefatigue during factory testing. The crack started at the site of an electrical arcout. 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.
Initial Inspection or Replacement
(f) Using the compliance schedule in Table 1 of this AD: (1) Visually inspect and eddy current inspect (ECI) applicable stage 5 LPT disks and applicable stage 6 LPT disks using paragraphs 3.C.(1) through 3.E.(6) of GE ASB No. CF34AL S/B 72A0173, Revision 3, dated July 20, 2004, if the inspections can be completed within 9 calendar months after the effective date of this AD; or
(2) If the inspections specified in paragraph (f)(1) of this AD cannot be completed within 9 calendar months after the effective date of this AD, replace applicable stage 5 LPT disks and applicable stage 6 LPT disks with a serviceable disk using the compliance schedule in Table 1 of this AD.
(3) The requirements of paragraphs (f)(1) and (f)(2) of this AD do not apply if the inspections were conducted using paragraph (g)(1) of this AD.
Table 1.Compliance Schedule
Then perform the actions defined in paragraph (f) of On the effective date of this AD, if this AD at next piecepart the disk has: exposure, not to exceed the accumulation of: (i) 14,750 or more cyclessincenew An additional 250 cyclesin (CSN) and has not been fluorescent service (CIS) after the penetrant inspected (FPI) at an effective date of this AD. earlier piecepart exposure.
(ii) 14,750 or more CSN and has been An additional 500 CIS after the FPI at an earlier piecepart exposure. effective date of this AD. (iii) 14,500 or more CSN but fewer than An additional 500 CIS after the 14,750 CSN. effective date of this AD. (iv) 14,250 or more CSN but fewer than An additional 750 CIS after the 14,500 CSN. effective date of this AD. (v) 13,000 or more CSN but fewer than An additional 1,000 CIS after 14,250 CSN. the effective date of this AD. (vi) 2,500 or more CSN but fewer than An additional 4,000 CIS after 13,000 CSN. the effective date of this AD, or 14,000 CSN, whichever comes first.
(vii) Fewer than 2,500 cyclessincenew 6,500 CSN.
(CSN).
(g) Before installation in an airplane:
(1) Visually inspect and ECI applicable stage 5 LPT disks and applicable stage 6 LPT disks installed in replacement engines or replacement LPT modules using paragraphs 3.C.(1) through 3.E.(6) of GE ASB No. CF34AL S/B 72A0173, Revision 3, dated July 20, 2004, if the inspections can be completed within 9 calendar months after the effective date of this AD; or
(2) If the inspections specified in paragraph (g)(1) of this AD cannot be completed within 9 calendar months after the effective date of this AD, replace applicable stage 5 LPT disks and applicable stage 6 LPT disks installed in replacement engines or replacement LPT modules with a serviceable disk.
Repetitive Inspections
(h) For stage 5 LPT disks and stage 6 LPT disks initially inspected as specified in paragraph (f)(1) or (g)(1) of this AD, perform repetitive visual inspections and ECIs within every 3,100 cyclessincelastinspection, using paragraphs 3.C.(1) through 3.E.(6) of GE ASB No. CF34AL S/B 72A0173, Revision 3, dated July 20, 2004, until the life limit of the part is reached.
Disks That Pass Inspection
(i) If a disk passes inspection, it must be reinstalled into the same LPT module it was removed from.
Optional Terminating Action
(j) Replacement of an applicable stage 5 LPT disk or applicable stage 6 LPT disk with a disk not listed in Figure 3 of GE ASB No. CF34AL S/B 72A0173, Revision 3, dated July 20, 2004, is
terminating action to the inspections required by this AD for that disk.
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Actions Completed per Previous Releases of Alert Service Bulletin CF34 AL S/B 72A0173
(k) Actions completed before the effective date of this AD using GE ASB No. CF34AL S/B 72A0173, dated April 2, 2004; or Revision 1, dated May 20, 2004; or Revision 2, dated June 22, 2004; or Revision 3, dated July 20, 2004; are considered acceptable for compliance with the corresponding action in this AD.
Definitions
(l) For the purposes of this AD, a serviceable disk is defined as a disk that has a SN not listed in Figure 3 of GE ASB No. CF34AL S/B 72A0173, Revision 3, dated July 20, 2004.
(m) For the purposes of this AD, the definition of piecepart exposure for the stage 5 LPT disk is when the disk is separated from the forward and aft bolted joints.
(n) For the purpose of this AD, the definition of piecepart exposure for the stage 6 LPT disk is when the disk is separated from the forward bolted joint.
(o) For the purposes of this AD, the definition of a replacement engine or replacement LPT module is an engine or LPT module that is not installed on an operational airplane on the effective date of this AD.
Alternative Methods of Compliance
(p) 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
(q) You must use GE ASB No. CF34AL S/B 72A0173, Revision 3, dated July 20, 2004, to perform the visual inspections, ECIs, and disk replacements required by this AD. The incorporation by reference of this publication was approved previously by the Director of the Federal Register as of August 16, 2004 (69 FR 45562; July 30, 2004), in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. You can get a copy from GE Aircraft Engines, 1000 Western Avenue, Lynn, MA 01910; Attention: CF34 Product Support Engineering, Mail Zone: 34017; telephone (781) 5946323; fax (781) 5940600, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202 7416030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html .
Related Information
(r) GE Alert Service Bulletin No. CF34AL S/B 72A0178 pertains 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. 0418635 Filed 81304; 8:45 am]
BILLING CODE 491013P

FOR FURTHER INFORMATION CONTACT Robert Grant, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 018035299; telephone (781) 2387757; fax (781) 2387199.