AD 2000-23-52 Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76A, S-76B, and S-76C Helicopters

Models named: S-76A, S-76B, S-76C. Read the applicability below — it usually turns on serial or part numbers too.

Model S-76A, S-76B, and S-76C helicopters, with main rotor shaft assembly (shaft), part number (P/N) 76351-09030 series or 76351-09630 series, installed, 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 (f) 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.

Required as indicated, unless accomplished previously. To prevent failure of the shaft and subsequent loss of control of the helicopter, accomplish the following: (a) Before further flight, perform a fluorescent penetrant inspection of the shaft in the area above the upper shaft output seal and below the lower hub attachment flange for any cracks in accordance with the Accomplishment Instructions, paragraphs 3.A.(1) through 3.A.(8), contained in Sikorsky Aircraft Corporation Alert Service Bulletin No. 76-66-31, Revision B, dated November 7, 2000 (ASB). Note 2: The fluorescent penetrant inspection specified in this AD is not the fluorescent penetrant inspection contained in paragraph 4 of Chapter 20-05-00 of the applicable maintenance manual. (b) Before the first flight of each day, visually inspect the shaft in the area above the upper shaft output seal and below the lower hub attachment flange for any cracks using a 10x or higher magnifying glass. Accomplish this inspection in accordance with the Accomplishment Instructions, paragraphs 3.B.(1) through 3.B.(5), of the ASB, except contacting Sikorsky Aircraft Corporation is not required by this AD. (c) At intervals not to exceed 20 hours time-in-service or 80 landings, whichever occurs first, perform a fluorescent penetrant inspection of the shaft in the area above the upper shaft output seal and below the lower hub attachment flange in accordance with the Accomplishment Instructions, paragraphs 3.C.(1) through 3.C.(5), of the ASB, except contacting Sikorsky Aircraft Corporation is not required by this AD. (d) If a crack is found as a result of any of the inspections, remove the shaft and replace it with an airworthy shaft that has been inspected in accordance with paragraph (a) of this AD before further flight. (e) Before further flight, shafts, P/N 76351-09030-series, serial numbers with a prefix of “B” and numbers 015-00700 through 00706, must be removed from service. (f) 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 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. (g) 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. (h) The fluorescent penetrant and visual inspections shall be done in accordance with the Accomplishment Instructions, paragraphs 3.A.(1) through 3.A.(8), 3.B.(1) through 3.B.(5), and 3.C.(1) through 3.C.(5), contained in Sikorsky Aircraft Corporation Alert Service Bulletin No. 76-66-31 (318B), Revision B, dated November 7, 2000. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Sikorsky Aircraft Corporation, Attn: Manager, Commercial Tech Support, 6900 Main Street, Stratford, Connecticut 06614, phone (203) 386-7860, fax (203) 386-4703. Copies may be inspected at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (i) This amendment becomes effective on February 16, 2001, to all persons except those persons to whom it was made immediately effective by Emergency AD 2000-23-52, issued November 9, 2000, which contained the requirements of this amendment. Issued in Fort Worth, Texas, on January 19, 2001. Henry A. Armstrong, Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 01-2611 Filed 1-31-01; 8:45 am] BILLING CODE 4910-13-U