Skip to Content

Proposed Rule

Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76A, S-76B and S-76C 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 the adoption of a new airworthiness directive (AD) for Sikorsky Aircraft Corporation Model S-76A, S-76B and S-76C helicopters. The AD would require removing and inspecting each main rotor spindle attachment bolt (bolt) to ensure that the correct bolts are installed. This proposal is prompted by the discovery of improper bolts installed on a helicopter during its production. The actions specified by the proposed AD are intended to detect installation of incorrect bolts, which could result in reduced hub or bolt fatigue life, separation of the main rotor blade at the spindle attachment, and subsequent loss of control of the helicopter.

DATES:

Comments must be received on or before August 19, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of the Regional Counsel, Southwest Region, Attention: Rules Docket No. 2001-SW-59-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. You may also send comments electronically to the Rules Docket at the following address: 9-asw-adcomments@faa.gov. 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.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Kirk Gustafson, Aviation Safety Engineer, Boston Aircraft Certification Office, Engine and Propeller Directorate, FAA, 12 New England Executive Park, Burlington, MA 01803, telephone (781) 238-7190, fax (781) 238-7170.

End Further Info End Preamble Start Supplemental Information

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 Start Printed Page 41876the 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. 2001-SW-59-AD.” The postcard will be date stamped and returned to the commenter.

Discussion

This document proposes the adoption of a new AD for Sikorsky Aircraft Corporation Model S-76A, S-76B and S-76C helicopters. The AD would require removing and inspecting each bolt to ensure that the correct bolts are installed. The bolt's complete part number is not visible, so it is necessary to measure each bolt to ensure the proper length bolt is installed. This proposal is prompted by the discovery of improper length bolts installed on a helicopter during its production. The manufacturer conducted subsequent inspections of additional helicopters, as well as structural assessments on spindle/hub attachments. A total of four helicopters were found to have incorrect bolts installed. The actions specified by the proposed AD are intended to detect installation of incorrect bolts, which could result in reduced hub or bolt fatigue life, separation of the main rotor blade at the spindle attachment, and subsequent loss of control of the helicopter.

The FAA has reviewed Sikorsky Aircraft Corporation Alert Service Bulletin No. 76-65-52 (321), dated July 24, 2001, which describes procedures for a one-time inspection of each bolt for the correct length during the 1,250 hour time-in-service (TIS) inspection.

This unsafe condition is likely to exist or develop on other helicopters of the same type design. Therefore, the proposed AD would require removing and inspecting each bolt to ensure that the correct bolts are installed.

The FAA estimates that 165 helicopters of U.S. registry would be affected by this proposed AD, that it would take approximately 6 work hours per helicopter to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Required parts would cost approximately $240 per helicopter. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $99,000, assuming all 40 bolts (per helicopter) are replaced.

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.

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:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

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

Start Authority

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

End Authority
[Amended]

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

Sikorsky Aircraft Corporation: Docket No. 2001-SW-59-AD.

Applicability: Model S-76A, S-76B and S-76C helicopters, except those having a serial number of 760501, or 760506 through 760515, 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 within 1,250-hour time-in-service or two years, whichever comes first, unless accomplished previously.

To detect installation of an incorrect main rotor spindle attachment bolt (bolt), which could result in reduced hub or bolt fatigue life, separation of the main rotor blade at the spindle attachment, and subsequent loss of control of the helicopter, accomplish the following:

(a) Remove and measure each bolt to ensure that the length is 1.181 ±.015 inches. There are 10 bolts per rotor spindle and 40 bolts per helicopter that require inspection.

(1) If 1 or 2 bolts are found on any spindle that are longer than 1.196 inches (1.181 inches + .015-inch permissible tolerance), visually inspect the main rotor hub internal threads for distortion and the hole-bottoms for scoring.

(i) If thread distortion or hole-bottom scoring is found, remove the rotor hub from service.

(ii) If no thread distortion or hole-bottom scoring is found, replace all 10 bolts with new airworthy bolts.

(2) If 3 or more bolts that exceed 1.196 inches are found on any spindle, remove and replace the main rotor hub with an airworthy main rotor hub.

(3) If any bolt is found that is shorter than 1.166 inches (1.181 inches−.015 permissible tolerance), replace it with a new airworthy bolt.

(b) Report the results of the inspections of the main rotor hubs whenever the bolts exceed 1.196 inches in length, within 5 calendar days of the inspection, to the Manager, Boston Aircraft Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone: (781) 238-7150; fax: (781) 238-7170. Include the following information in the report:

(1) Serial number of the helicopter.

(2) Quantity of incorrect bolts.

(3) Description of thread distortion or hole-bottom scoring caused by each bolt. Information collection requirements contained in this AD have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056. Start Printed Page 41877

(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, Engine and Propeller Directorate, 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 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 June 10, 2002.

Larry M. Kelly,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 02-15551 Filed 6-19-02; 8:45 am]

BILLING CODE 4910-13-P