AD 2001-03-51 Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76B and S-76C Helicopters

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

Model S-76B and S-76C helicopters, with main rotor shaft assembly (shaft), part number (P/N) 76351-09630 all dash numbers, serial number (S/N) C213-00274, C213-00275, C213-00276, C213-00277, C213-00278, C213-00279, C213-00280, C213-00282, C213-00292, C213-00294, C213-00295, C213-00296, C213-00297, C213-00299, and C213-00300, 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 (d) 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 and thereafter at intervals not to exceed 20 hours time-in-service (TIS) or 80 landings, whichever occurs first, conduct a fluorescent penetrant inspection (FPI) in the area above the uppers shaft output seal and below the lower hub attachment flange in accordance with the Accomplishment Instructions, paragraphs 3.B.(1) through 3.B.(5), of Sikorsky Aircraft Corporation (Sikorsky) Alert Service Bulletin (ASB) No. 76-66-32A, Revision A, dated January 17, 2001. Contacting Sikorsky is not required by this AD. If a crack is found, replace the shaft with an airworthy shaft before further flight. Note 2: Accomplishing the FPI before further flight is not required if previously accomplished in accordance with the Accomplishment Instructions, paragraphs 3.C.(1) through 3.C.(5), of Sikorsky ASB No. 76-66-31B, Revision B, dated November 7, 2000. (b) On or before 1000 hours TIS, replace each affected shaft with an airworthy shaft. (c) This AD revises the Limitations section of the maintenance manual by establishing a retirement life of 1000 hours TIS for the affected shafts. (d) 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. (e) 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 if the FPI or a visual inspection, using a 10X or higher magnifying glass, does not reveal a crack. (f) The FPI shall be done in accordance with the Accomplishment Instructions, paragraphs 3.B.(1) through 3.B.(5), of Sikorsky Aircraft Corporation Alert Service Bulletin No. 76-66-32A, Revision A, dated January 17, 2001. This incorporation by reference was approved 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) 386-3001, fax (203) 386-5983. 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. (g) This amendment becomes effective on March 21, 2001, to all persons except those persons to whom it was made immediately effective by Emergency AD 2001-03-51, issued January 30, 2001, which contained the requirements of this amendment. Issued in Fort Worth, Texas, on February 20, 2001. Eric Bries, Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 01-5165 Filed 3-5-01; 8:45 am] BILLING CODE 4910-13-M