Airworthiness directives: CFE Co.,

[Federal Register: September 28, 1999 (Volume 64, Number 187)]

[Proposed Rules]

[Page 52259-52260]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr28se99-19]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-39-AD]

RIN 2120-AA64

Airworthiness Directives; CFE Company Model CFE738-1-1B Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to CFE Company Model CFE738-1-1B turbofan engines. This proposal would require, on certain engines identified by serial numbers, a one-time visual inspection of Stage 2 high pressure turbine (HPT) aft cooling plates, for nicks, dents, and scratches, and if present, dimensional inspection of indentation depth, repair if indentation is within acceptable limits, and, if necessary, replacement with serviceable parts. This AD would also require inspection of the Stage 2 HPT rotor disk post aft surface which mates with the Stage 2 HPT aft cooling plate, for raised metal and removal of the raised metal, if present. This proposal is prompted by reports of dented Stage 2 HPT aft cooling plates which occurred during the assembly of the cooling plate to the Stage 2 disk due to raised metal on the stage 2 HPT disk post aft mating surface. The actions specified by the proposed AD are intended to prevent aft HPT cooling plate failure, which could result in an uncontained engine failure and damage to the airplane.

DATES: Comments must be received by November 29, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-39-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address: ``9-ane- adcomment@faa.gov''. Comments sent via the Internet must contain the docket number in the subject line. Comments may be inspected at this location between 8:00 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays.

The service information referenced in the proposed rule may be obtained from CFE Company, Data Distribution, MS 64-03/2101-201, P.O. Box 52170, Phoenix, AZ 85972-2170; telephone (602) 365-2493, fax (602) 365-5577. This information may be examined at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Keith Mead, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (781) 238- 7744, 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 notice 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 filedin the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 99-NE-39-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

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. 99-NE-39-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

The Federal Aviation Administration (FAA) has received reports of certain Stage 2 high pressure turbine (HPT) aft cooling plates, installed on CFE Company Model CFE738-1-1B turbofan engines, that were dented during the assembly of the cooling plate to the stage 2 disk due to raised metal on the aft mating face of the Stage 2 HPT rotor disk post. During the assembly of the high-pressure turbine rotor, the Stage 2 disk is restrained with a special tool fixture. It has been determined that a condition occurring in this fixture as early as January 1998, may have resulted in raised metal on the disk post aft surface, which interfaces with the aft cooling plate. The higher the raised metal on the disk post, the deeper the dent in the cooling plate. The fixture has been repaired to prevent further occurrences and engines which may be effected by this condition have been identified by serial numbers. Analysis indicates that nicks, dents, and scratches on the Stage 2 HPT aft cooling plate exceeding a certain depth would result in a reduction in part cyclic life. This condition, if not corrected, could result in aft HPT cooling plate failure, which could result in an uncontained engine failure and damage to the airplane.

Service Information

The FAA has reviewed and approved the technical contents of CFE Alert

[[Page 52260]]

Service Bulletin (ASB) CFE738-A72-8031, Revision 1, dated June 23, 1999, that describes the dimensional inspection procedures for indentation depth on aft HPT cooling plates, inspection of the stage 2 HPT rotor disk for raised metal, and the acceptance and repair criteria of the Stage 2 HPT aft cooling plate and HPT rotor disk.

Proposed Actions

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require, on engines identified by S/N, a one-time visual inspection of Stage 2 high pressure turbine (HPT) aft cooling plates for nicks, dents, and scratches, and if present, dimensional inspection of indentation depth, repair if indentation is within acceptable limits, and, if necessary, replacement with serviceable parts. This AD would also require inspection of the Stage 2 HPT rotor disk post aft surface which mates with the Stage 2 HPT aft cooling plate, for raised metal, and, removal of the raised metal, if present. The inspections would be required at the next shop visit after the effective date of this AD where the HPT assembly is sufficiently disassembled to afford access to the Stage 2 HPT aft cooling plate, but not later than 4,500 part cycles since new (CSN) in accordance with the ASB described previously.

Economic Analysis

There are approximately 72 engines of the affected design in the worldwide fleet. The FAA estimates that 48 engines installed on aircraft of US registry would be affected by this proposed AD, that it would take approximately 4 work hours per engine to accomplish the proposed inspection if the inspection did not take place during scheduled maintenance, and that the average labor rate is $60 per work hour. Required parts would cost approximately $1,536 per engine. Based on these figures, the total cost impact of the proposed AD on US operators is estimated to be $106,560.

The regulations proposed herein would not have substantial direct effects 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. Therefore, in accordance with Executive Order 12612, it is determined that this proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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:

   Company: Docket No. 99-NE-39-AD.

   Applicability: CFE Model CFE738-1-1B turbofan engines, serial numbers (S/Ns) 105267 through 105339, inclusive. These engines are installed on but not limited to Dassault-Breguet Falcon 2000 series aircraft.

   Note 1: This airworthiness directive (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 (b) 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: Required as indicated, unless accomplished previously.

   (a) At the next engine shop visit after the effective date of this AD where the HPT assembly is sufficiently disassembled to afford access to the Stage 2 HPT aft cooling plate, but not later than 4500 part cycles-since-new (CSN), accomplish the following in accordance with CFE Alert Service Bulletin (ASB) No. CFE738-A72- 8031, Revision 1, dated June 23, 1999 as follows:

   (1) Inspect the stage 2 HPT aft cooling plate for nicks, dents, and scratches on surface D in accordance with the requirements of ASB No. CFE738-A72-8031 paragraph 2.B.(1).

   (2) Repair those stage 2 HPT aft cooling plates with indentation less than 0.003 inch deep in accordance with ASB No. CFE738-A72-8031 paragraph 2.B.(1).

   (3) Remove from service prior to further flight those stage 2 HPT aft cooling plates which have nicks, dents, and/or scratches that exceed the acceptance limits in accordance with ASB No. CFE738- A72-8031 paragraph 2.B.(1), and replace with a serviceable part.

   (4) Inspect the stage 2 HPT rotor disk post aft mating surface for raised metal, and remove raised metal if present in accordance with ASB No. CFE738-A72-8031 section 2.B.(2).

   (b) 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 shall 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.

   (c) Special flight permits may be issued in accordance with sections 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 inspection requirements of this AD can be accomplished.

   Issued in Burlington, Massachusetts, on September 20, 1999. David A. Downey, Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service.

   [FR Doc. 99-25122Filed9-27-99; 8:45 am]

   BILLING CODE 4910-13-U