AD 97-14957

[Federal Register Volume 62, Number 110 (Monday, June 9, 1997)] [Proposed Rules] [Pages 31370-31371] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 97-14957]

======================================================================== Proposed Rules Federal Register ________________________________________________________________________ This section of the FEDERAL REGISTER contains notices to the public of the proposed issuance of rules and regulations. The purpose of these notices is to give interested persons an opportunity to participate in the rule making prior to the adoption of the final rules. ========================================================================

Federal Register / Vol. 62, No. 110 / Monday, June 9, 1997 / Proposed Rules

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-ANE-18-AD] RIN 2120-AA64

Airworthiness Directives; General Electric Company CT58 Series Turboshaft Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness directive (AD) that is applicable to General Electric Company CT58 series turboshaft engines. This proposal would require removal from service of certain stage 1 and 2 forward cooling plates, and stage 2 aft cooling plates, and replacement with serviceable parts. This proposal is prompted by reports of certain cooling plates forged with contaminated alloy that could reduce the lives of the parts. The actions specified by the proposed AD are intended to prevent cooling plate fracture, which could result in a contained engine failure, and an inflight engine shutdown.

DATES: Comments must be received by August 8, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 97-ANE-18-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address: ``9-ad- [email protected]''. 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 General Electric Company (GE), 1000 Western Ave., Lynn, MA 01909; telephone (671) 594-9894, fax (617) 594-1527. This information may be examined at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Diane Cook, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone (617) 238- 7134, fax (617) 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 filed in 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 97-ANE-18-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 Assistant Chief Counsel, Attention: Rules Docket No. 97-ANE-18-AD, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

The Federal Aviation Administration (FAA) has received reports of certain stage 1 and stage 2 forward cooling plates and stage 2 aft cooling plates, installed on General Electric Company (GE) Models CT58- 110-1, -110-2, -140-1, -140-2, and T58-GE-3/-5/-8F/-10/-100 turboshaft engines, forged with contaminated alloy that could reduce the lives of the parts. Iron-rich inclusions were found in forgings produced by a vendor using A286 material. These inclusions were first found on parts from two heat lots during the normal Vacuum Induction Melt (VIM) in- process macroetch inspections. The parts from these two heat lots were then scrapped. Corrective actions to the VIM process were implemented to prevent the reoccurrence of iron-rich inclusions. Records of all heat lots produced from this vendor prior to the implementation of the corrective actions, totaling 56 heat lots, were reviewed. Twenty five out of the 56 heat lots were determined to be potentially contaminated. Approximately 300 GE CT58 cooling plates were produced from one potentially contaminated heat lot. A retired cooling plate from this suspected heat lot was macroetch inspected and was found with an inclusion. This condition, if not corrected, could result in cooling plate fracture, which could result in a contained engine failure, and an inflight engine shutdown. The FAA has reviewed and approved the technical contents of GE Aircraft Engines CT58 Service Bulletin (SB) No. 72-188 (CEB-293), dated March 25, 1997, that describes procedures for removal from service of certain stage 1 and 2 forward cooling plates, and stage 2 aft cooling plates, and replacement with serviceable parts. 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 removal from service of certain stage 1 and 2 forward cooling plates, and stage 2 aft cooling plates, and replacement with serviceable parts. The actions would be required to be accomplished in accordance with the SB described previously.

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There are approximately 400 engines of the affected design in the worldwide fleet. The FAA estimates that 126 engines installed on aircraft of U.S. registry would be affected by this proposed AD, and that it would not take any additional work hours per engine to accomplish the proposed actions at next part exposure. Required parts would cost approximately $2,730 per engine, based on the estimated current part cost. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $343,980. The manufacturer, however, has advised the FAA of a program to prorate the cost of required parts downward by a factor equal to the quotient of the difference between the original life limit of 4,000 hours time in service and the total cycles of life consumed at time of removal, divided by the original life limit. Therefore, the actual cost to operators may be less than the FAA's estimate. 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:

General Electric Company: Docket No. 97-ANE-18-AD.

Applicability: General Electric Company (GE) Models CT58-110-1, -110-2, -140-1, and -140-2 , and T58-GE-3/-5/-8F/-10/-100 series turboshaft engines, with stage 1 forward cooling plate, Part Number (P/N) 37C300055P101, stage 2 forward cooling plate, P/N 3000T88P02, and stage 2 aft cooling plate, P/N 3002T27P01, installed. These engines are installed on but not limited to Boeing Vertol 107 series, and Sikorsky S61 and S62 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. To prevent cooling plate fracture, which could result in a contained engine failure and an inflight engine shutdown, accomplish the following: (a) Remove from service affected cooling plates, listed by serial number in GE Aircraft Engines CT58 Service Bulletin (SB) No. 72-188 (CEB-293), dated March 25, 1997, and replace with serviceable parts, at the next part exposure, or next light overhaul, whichever occurs first, but not to exceed 1,000 hours time in service (TIS) for engines installed on aircraft that have engaged in Repetitive Heavy Lift (RHL) operations, or 2,000 hours TIS for engines installed on aircraft that have never engaged in RHL operations, in accordance with that SB. (b) For the purpose of this AD, the following definitions apply: (1) RHL operation is defined as performing more than 10 lift- carry-drop cycles per hour TIS without landing, or more than 10 takeoffs and landings per hour TIS. (2) Light overhaul is defined as scheduled engine maintenance that allows the engine to continue in service until scheduled major overhaul time is reached. (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. The request shall be forwarded through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.

Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.

(d) 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 aircraft to a location where the requirements of this AD can be accomplished.

Issued in Burlington, Massachusetts, on May 27, 1997. Jay J. Pardee, Manager, Engine and Propeller Directorate, Aircraft Certification Service. [FR Doc. 97-14957 Filed 6-6-97; 8:45 am] BILLING CODE 4910-13-U