AD 2011-12-03 Airworthiness Directives; Sikorsky Aircraft Corporation (Sikorsky) Model S-92A Helicopters

Models named: S-92A. Read the applicability below — it usually turns on serial or part numbers too.

Model S-92A helicopters with main gearbox (MGB) upper housing assembly, part number (P/N) 92351-15110-042, -043, -044, -045, or -046, installed, certificated in any category.

For each MGB upper housing assembly with 700 or more hours time-in-service (TIS), within 30 hours TIS, unless already done, or for each MGB upper housing assembly with more than 500 hours TIS but less than 700 hours TIS, within 50 hours TIS, unless already done, and for all helicopters thereafter at intervals not to exceed 50 hours TIS: (1) Clean and Eddy Current inspect the forward, left, and right MGB mounting foot ribs for a crack by following the Accomplishment Instructions, paragraphs 3.C. through 3.D.(2)(d), of Sikorsky Alert Service Bulletin No. 92-63-025A, Revision A, dated May 12, 2011 (ASB); or (2) Clean and fluorescent penetrant inspect (FPI) the MGB mounting foot ribs for a crack by following the Accomplishment Instructions, paragraphs 3.E.(1) through 3.E.(5), of the ASB. (3) An inspector qualified to ASNT Level II or equivalent is required to perform the nondestructive inspection (NDI), by Eddy Current or FPI, of the left, right, and forward MGB mounting foot ribs for a crack. (f) If there is a crack, before further flight, replace the MGB upper housing assembly with an airworthy MGB upper housing assembly. Note: Sikorsky has developed a Phase III MGB upper housing assembly, P/N 92351-15310-041, is not subject to the “Applicability” of this AD. Alternative Methods of Compliance (AMOCs) (g)(1) The Manager, Boston Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested, using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the ACO, send it to the attention of the person identified in the Additional Information section of this AD. (2) Before using any approved AMOC, we request that you notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. Additional Information (h) For more information about this AD, contact 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, E-mail Michael.Schwetz@faa.gov. Material Incorporated by Reference (i)(1) Inspect the MGB upper housing assembly mounting foot ribs for a crack by following the specified portions of Sikorsky Alert Service Bulletin No. 92-63-025A, Revision A, dated May 12, 2011. The Director of the Federal Register approved the incorporation by reference of the service information. (2) For service information identified in this AD, contact 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. (3) 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 an NARA facility, call 202-741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

This AD is prompted by a report of a crack found on the MGB left mounting foot forward rib that may not be found during a visual inspection. We are issuing this AD to prevent loss of a MGB and subsequent loss of control of the helicopter.