AD 2002-21-07

This amendment adopts a new airworthiness directive (AD) for the specified Sikorsky Aircraft Corporation (Sikorsky) model helicopters that requires removing and inspecting each main rotor spindle attachment bolt (bolt) to ensure that the correct bolts are installed. This amendment is prompted by the discovery of improper bolts installed on a helicopter during its production. The actions specified by this 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.

Final rule.

2002-21-07 Sikorsky Aircraft Corporation: Amendment 39-12913. 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 addressit.

Compliance: Required within 1,250-hours time-in-service or 2 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, replaceall 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.

Note 2: Sikorsky Aircraft Corporation Alert Service Bulletin No. 76-65-52 (321), dated July 24, 2001, pertains to the subject 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, 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 3: 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 21.197and 21.199 to operate the helicopter to a location where the requirements of this AD can be accomplished.

(e) This amendment becomes effective on November 25, 2002.

A proposal to amend 14 CFR part 39 to include an AD for Sikorsky Model S-76A, S-76B and S-76C helicopters was published in the Federal Register on June 20, 2002 (67 FR 41875). That action proposed to require removing and inspecting each bolt to ensure that the correct bolts are installed.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule with one change. A "note" has been added following paragraph (b)(3) referencing the alert service bulletin that pertains to the subject of the AD. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

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

The regulations adopted herein will 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 final rule does not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not havea significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from 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.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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: