Airworthiness Directive · Amendment 39-16522 · Sikorsky Aircraft Corporation (Sikorsky) Model S-92A Helicopters
Sikorsky Aircraft Corporation (Sikorsky) Model S-92A Helicopters
Model S-92A helicopters, with main gearbox (MGB) assembly, part number (P/N) 92351-15000-042, -043, or -044, with MGB housing, P/N 92351-15110-042, -043, -044, -045, or -046, installed, certificated in any category.
This amendment supersedes an existing airworthiness directive (AD) for Sikorsky Model S-92A helicopters that currently requires cleaning and inspecting each main gearbox (MGB) assembly mounting foot pad and rib for a crack and corrosion. If you do not find a crack, the AD requires applying a corrosion preventive compound. If you find a crack, the AD requires replacing the MGB before further flight. If you find corrosion, bubbled paint, or paint discoloration, the AD requires you to repair the MGB before further flight. This amendment retains the current requirements and expands the applicability to include another part-numbered MGB assembly and MGB housing. This amendment is prompted by the need to expand the applicability to include another MGB assembly and MGB housing that is prone to the same cracks and corrosion as the MGB listed in the current AD. The actions specified by this AD are intended to prevent the loss of the MGB and subsequent loss of control of the helicopter.
To prevent loss of an MGB and subsequent loss of control of the helicopter, do the following:
(a) Within 10 hours time-in-service (TIS), unless accomplished previously, and thereafter at intervals not to exceed 10 hours TIS, clean and inspect each MGB assembly mounting foot pad and rib for a crack and corrosion in the area depicted in Figure 1 and as shown in the examples in Figures 2, 3, and 4 of Sikorsky Alert Service Bulletin No. 92-63-020, dated September 11, 2009 (ASB). If no crack is found, apply the corrosion preventive compound to each foot pad and rib area.
Note 1: When conducting a visual inspection, use a bright, non-LED light. (1) If you find a crack, replace the MGB before further flight. (2) If you find corrosion, bubbled paint, or paint discoloration, before further flight, repair the affected area.
Note 2: Even though MGB assembly, P/N 92351-15000-044, with MGB housing, P/N 92351-15110-046, is not included in the ASB, following the Accomplishment Instructions in the ASB accomplishes the intent of this AD.
(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, ATTN: Michael Schwetz, Aviation Safety Engineer, 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 6320: Main Rotor Gearbox.
(d) Do the inspections by following the specified portions of Sikorsky Alert Service Bulletin No. 92-63-020, dated September 11, 2009. The Director of the Federal Register approved this incorporation by reference under 5 U.S.C. 552(a) and 1 CFR part 51 as of February 19, 2010 (75 FR 5684, February 4, 2010). 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.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
