2010-23-24: Gear

2010-23-24 Sikorsky Aircraft Corp.: Amendment 39-16514; Docket No. FAA-2010-0490; Directorate Identifier 2010-SW-037-AD. Applicability: Model S-70A and S-70C helicopters with a tail gearbox output bevel gear (gear), part number 70358-06620, certificated in any category. Compliance: Required as indicated. To prevent a tail rotor separating, loss of tail rotor control, and subsequent loss of control of the helicopter, do the following: (a) Within 500 hours time-in-service (TIS), unless accomplished previously, and thereafter at intervals not to exceed 500 hours TIS, remove the tail rotor servo control and pitch beam shaft, and using a Level II Ultrasonic Testing Technician or equivalent, ultransonic inspect the gear for a crack. Ultrasonic inspect the gear by following paragraphs A.(5)a. through A(5)n. of Special Service Instructions No. 70-121A, Revision A, dated May 21, 2009. If you find a crack, before further flight, replace the gear with an airworthy gear.(b) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Manager, Boston Aircraft Certification Office, FAA, Attn: Michael Schwetz, Aviation Safety Engineer, Boston Aircraft Certification Office, 12 New England Executive Park, Burlington, MA 01803, telephone (781) 238-7761, fax (781) 238-7170, for information about previously approved alternative methods of compliance. (c) The Joint Aircraft System/Component (JASC) Code is 6520: Tail rotor gearbox. (d) The inspections shall be done in accordance with the specified portions of Sikorsky Special Service Instructions No. 70- 121A, Revision A, dated May 21, 2009. The Director of the Federal Register approved this incorporation by reference 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 Technical Support, mailstop s581a, 6900 Main Street, Stratford, CT, telephone (203) 383-4866, e-mail address tsslibrary@sikorsky.com, or at http:/ /www.sikorsky.com. 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 National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http:// www.archives.gov/federal_register/code_of_federal_regulations/ ibr_locations.html. (e) This amendment becomes effective on December 22, 2010.