Sikorsky S-92 Series Helicopters
Sikorsky S-92 Series Helicopters
Sikorsky S-92 Series Helicopters
| AD/S-92/6 | Main Gearbox Filter BowlAssembly Mounting Studs | 5/2009 TX |
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| Applicability: | Sikorsky Aircraft Corporation S-92A helicopters with a main gearbox assembly, part number (P/N) 92351-15110-042, -043, or -044, that is not marked with “TS-062-01” near the P/N. |
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| Requirement: | 1. Remove the titanium studs by following the accomplishment instructions in Sikorsky Alert Service Bulletin (ASB) No. 92-63-014, Rev A dated20 March 2009 paragraph 3.A.2. Visually inspect the tapped holes and the main gearbox housing lockring counterbore for damage.Note 1: Figure 1 of the ASB contains guidance for removal and installation of the studs.3. Install steel studs and mark the main gearbox housing as “TS-062-01” near the P/N by following the accomplishment instructions of Sikorsky ASB No.92-63-014 Rev A paragraph 3.C.Note 2: FAA Emergency AD 2009-07-053 dated 23 March 2009 refers. |
| Compliance: | Before further flight after the effective date of this AD unless previously accomplished. |
| This Airworthiness Directive becomes effective on 27 March 2009. | |
| Background: | This AD is in response to the failure of 2 main gearbox filter bowl studs that were found broken during a fatal accident investigation in Canada. Prior to this accident the manufacture was investigation a July 2008 incident in Australia that also involved broken studs. In both cases the broken studs resulted in rapid loss of oil.This AD requires the replacement of titanium studs with steel studs. |
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James Coyne
Delegate of the Civil Aviation Safety Authority
25 March 2009