03-29219. Airworthiness Directives; Sikorsky Aircraft Corporation Model S-61L, S-61N, S-61-NM, and S-61R Helicopters

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes adopting a new airworthiness directive (AD) for the specified Sikorsky Aircraft Corporation (Sikorsky) model helicopters. The AD would require installing a Number 5 bearing chip detector in each engine, installing an on-board chip detector annunciation system, and revising the Rotorcraft Flight Manual (RFM) to add procedures for crew response to an on-board chip detector annunciation. This proposal is prompted by reports of the failure of the engine's Number 5 bearing that resulted in erratic movement of the high-speed engine-to-transmission shaft (shaft), oil leakage, an in-flight fire and an emergency landing. The actions specified by the proposed AD are intended to detect an impending engine bearing (bearing) failure and prevent a bearing failure, oil leakage, severing of the shaft housing, an uncontained in-flight fire, and a subsequent immediate emergency landing.

DATES:

Comments must be received on or before January 23, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2003-SW-35-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. You may also send comments electronically to the Rules Docket at the following address: [e-mail]. Comments may be inspected at the Office of the Regional Counsel between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT:

Kirk Gustafson, Aviation Safety Engineer, Boston Aircraft Certification Office, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803, telephone [phone], fax [phone].

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 will be considered before taking action on the proposed rule. The proposals contained in this document 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 mailed comments submitted in response to this proposal must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket No. 2003-SW-35-AD.” The postcard will be date stamped and returned to the commenter.

Discussion

This document proposes adopting a new AD for Sikorsky Model S-61L, S-61N, S-61-NM, and S-61R helicopters. The AD would require, within 60 days, installing a chip detector for the Number 5 engine bearing, installing an on-board chip detector annunciation system, and providing in the Emergency Procedures section of the RFM the emergency procedures for the flight crew to follow in the event that the engine chip detector warning light comes on during flight operations. This proposal is prompted by at least five similar events that varied in severity, in which the Number 5 bearing on the high-speed shaft connecting the engine to the transmission failed. Failure of this engine bearing resulted in uneven rotation of the shaft, leakage of engine oil that may be ignited by friction-induced heat, failure of the shaft housing, which is part of the fire containment system, and an uncontained fire. In the most severe incident, the fire consumed the aircraft after a successful emergency landing. The actions specified by the proposed AD are intended to detect an impending bearing failure and to prevent a bearing failure, oil leakage, severing of the shaft housing, an uncontained in-flight fire, and a subsequent immediate emergency landing.

The FAA has reviewed General Electric Aircraft Engine CT58 Service Bulletin Number 72-0195, dated May 1, 2003, which describes procedures for installing an electrical chip detector (either part number 3018T72P01 or 3049T42P01) in the CT58 engine power turbine accessory drive assembly. The FAA has also reviewed Sikorsky Aircraft Corporation Alert Service Bulletin No. 61B30-15, dated June 9, 2003, which describes procedures for installing an on-board cockpit annunciation system that interfaces with these engine chip detectors, as a means to detect metallic chips in the event of deterioration of the Number 5 bearing in either engine.

This unsafe condition is likely to exist or develop on other helicopters of the same type design. Therefore, the proposed AD would require, within 60 days, installing a chip detector for the No. 5 bearing, installing an on-board chip detector annunication system, and revising the RFM to add procedures for crew response to an on-board chip detector annunciation. The actions would be required to be accomplished in accordance with the two service bulletins described previously.

On July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's AD system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. Because we have now included this material in part 39, we no longer need to include it in each individual AD.

The FAA estimates that this proposed AD would affect 21 helicopters of U.S. registry, and the proposed actions would take approximately 81.5 work hours per helicopter to accomplish at an average labor rate of $65 per work hour. Required parts would cost approximately $1,940 per helicopter. Based on these figures, the total cost impact of the proposed AD on U.S. operators would be $7,238 per helicopter, or $151,998 for the entire fleet.

The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

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.

§ 39.13

[Amended]

2. Section 39.13 is amended by adding a new airworthiness directive to read as follows:

Sikorsky Aircraft Corporation: Docket No. 2003-SW-35-AD.

Applicability: Model S-61L, S-61N, S-61-NM, and S-61R helicopters.

Compliance: Required within 60 days, unless accomplished previously.

To detect impending engine bearing (bearing) failure and prevent a bearing failure, oil leakage, severing of the shaft housing, an uncontained in-flight fire, and a subsequent immediate emergency landing, accomplish the following:

(a) Install an engine chip detector, part number 3049T42P01 or 3018T72P01, in the engine power turbine accessory drive assembly in accordance with the Accomplishment Instructions, paragraphs 3.A. and 3.B., in General Electric Aircraft Engines CT58 Service Bulletin Number 72-0195, dated May 1, 2003.

(b) Install an on-board engine chip detector annunciation system in accordance with Sikorsky Aircraft Corporation Alert Service Bulletin No. 61B30-15, dated June 9, 2003 (ASB). For helicopters with a master warning caution panel (MWCP) manufactured by United Controls or Sundstrand Data, install in accordance with paragraph 3.B. of the ASB. For helicopters with an MWCP manufactured by Grimes Mfg., install in accordance with paragraph 3.C. of the ASB.

(c) After accomplishing paragraph (b) of this AD, before further flight, perform a functional test of the engine chip detector system and repeat the functional test at intervals not to exceed 150 hours TIS in accordance with the Accomplishment Instructions, paragraph 3.D., of the ASB.

(d) Insert the emergency procedures for an on-board engine chip detector warning light illumination into the Emergency Procedures section of the applicable Rotorcraft Flight Manual in accordance with the Accomplishment Instructions, paragraph 3.E., of the ASB.

(e) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Boston Aircraft Certification Office, Engine and Propeller Directorate, FAA, for information about previously approved alternative methods of compliance.

Issued in Fort Worth, Texas, on November 17, 2003.

David A. Downey,

Manager, Rotorcraft Directorate, Aircraft Certification Service.