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Proposed Rule

Airworthiness Directives; Sikorsky Aircraft Corporation (Sikorsky) Model S-76A Helicopters

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes adopting a new airworthiness directive Start Printed Page 15281(AD) applicable to Sikorsky Model S-76A helicopters. The AD would require inspecting at specified intervals until installing a soft-start assembly retrofit kit on the air conditioning system to prevent a continuous flow of current through the soft-start resistor. This proposal is prompted by a report of overheating of the soft-start assembly. The actions specified by the proposed AD are intended to prevent overheating of the air conditioning soft-start assembly, damage in the lower tailcone, an electrical fire, and subsequent loss of control of the helicopter.

DATES:

Comments must be received on or before May 22, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 99-SW-37-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. Comments may be inspected at this location between 9:00 am and 3:00 pm, Monday through Friday, except Federal holidays.

The service information referenced in the proposed rule may be obtained from Sikorsky Aircraft Corporation, Attn: Manager, Commercial Tech Support, 6900 Main Street, P.O. Box 9729, Stratford, Connecticut 06615-9129, phone (203) 386-7860, fax (203) 386-4703. This information may be examined at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas.

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FOR FURTHER INFORMATION CONTACT:

Terry Fahr, Boston Aircraft Certification Office, 12 New England Executive Park, Burlington, MA 01803, telephone (781) 238-7155, fax (781) 238-7199.

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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 No. 99-SW-37-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, Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 99-SW-37-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Discussion

This document proposes adopting a new AD applicable to Sikorsky Model S-76A helicopters. The AD would require inspecting the soft-start assembly at intervals not to exceed 25 hours time-in-service until installing a soft-start assembly retrofit kit on the Aero Aire Air Conditioning System, part number (P/N) S-76A-1-2, in 120 calendar days to prevent a continuous flow of current through the soft-start resistor. This proposal is prompted by a report of overheating of the air conditioning soft-start assembly. This condition, if not corrected, could cause serious secondary damage in the lower tailcone, an electrical fire, and subsequent loss of control of the helicopter.

The FAA has reviewed Sikorsky Alert Service Bulletin 76-21-4A, dated February 24, 1998 (ASB). The ASB refers operators to procedures in Aero Aire Corp. Service Bulletins 970001, Revision A, dated September 18, 1997, for inspecting the soft-start assembly, and 970002, dated December 18, 1997, for installing a soft-start assembly retrofit kit, P/N 76SB001, on the Aero Aire Air Conditioning System, P/N S-76A-1-2, on Sikorsky Model S-76A helicopters. The ASB states the procedures are necessary to prevent overheating of the air conditioning soft-start assembly that could cause serious secondary damage in the lower tailcone.

Since an unsafe condition has been identified that is likely to exist or develop on other Sikorsky Model S-76A helicopters of the same type designs, the proposed AD would require inspecting the soft start assembly at intervals not to exceed 25 hours time-in-service until installing a soft-start control assembly retrofit kit on the Aero Aire Air Conditioning System, P/N A-76A-1-2, within 120 calendar days. The actions would be required to be accomplished in accordance with the Aero Aire service bulletins described previously.

The FAA estimates that 9 helicopters of U.S. registry would be affected by this proposed AD, that it would take approximately 3 work hours per helicopter to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Aero Aire Service Bulletin No. 97002 states that the retrofit kit will be provided at no charge. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $1620.

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, 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.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

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:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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Start Printed Page 15282
[Amended]

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

Sikorsky Aircraft Corporation:

Docket No. 99-SW-37-AD.

Applicability: Model S-76A helicopters with Aero Aire Air Conditioning System, part number (P/N) S-76A-1-2, modified in accordance with Supplemental Type Certificate SH4680SW, certificated in any category.

Note 1:

This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters 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 (c) 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 overheating of the air conditioning soft-start control assembly, damage in the lower tailcone, a fire, and subsequent loss of control of the helicopter, accomplish the following:

(a) Within 25 hours time-in-service (TIS) and thereafter at intervals not to exceed 25 hours TIS, inspect the soft-start control assembly in accordance with the Accomplishment Instruction, Section III, of Aero Aire Corporation Service Bulletin No. 970001, Revision A, dated September 18, 1997, except neither contact nor return of the soft-start controller unit is required.

(b) Within 120 calendar days, install a soft start assembly retrofit kit (kit), P/N 76SB001, in accordance with the Accomplishment Instructions, Section III, of Aero Aire Corporation Service Bulletin 970002, dated December 18, 1997. Installing the kit is terminating action for the requirements of this AD.

(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, Boston Aircraft Certification Office, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Boston Aircraft Certification Office.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Boston Aircraft 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 helicopter to a location where the requirements of this AD can be accomplished.

Start Signature

Issued in Fort Worth, Texas, on March 15, 2000.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

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[FR Doc. 00-7112 Filed 3-21-00; 8:45 am]

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