Airworthiness Directive · Amendment 39-17122 · Main rotor gearbox
Sikorsky Aircraft Corporation Helicopters
This AD applies to Model S-92A helicopters, serial numbers 920006 through 920155, certificated in any category.
We are adopting a new airworthiness directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters. This AD requires inspecting the main gearbox (MGB) for a crack. This AD is prompted by a crack in the cored passage of the MGB housing, which may be indicated by oil on the housing. These actions are intended to detect a crack in the MGB housing, which could result in loss of oil, failure of the MGB, and subsequent loss of control of the helicopter.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
Within 10 hours time-in-service (TIS) or 15 days, whichever occurs earlier, and thereafter before the first flight of each day, not to exceed 10 hours TIS between inspections, accomplish the following:
(1) Clean and inspect, using a 10x or higher power magnifying glass, the MGB housing for a crack in the inspection area shown in Figure 1 of Sikorsky S-92 Alert Service Bulletin No. ASB 92-63-032 Basic Issue, dated December 22, 2011.
Note to paragraph (e)(1) of this AD: A crack may be indicated by the presence of oil in the inspection area of the MGB housing.
(2) If there is a crack, before further flight, replace the MGB with an airworthy MGB.
(3) Compliance with the one-time eddy-current inspection of the main module assembly of the MGB in accordance with the Accomplishment Instructions, paragraph 3.C, of Sikorsky S-92 ASB No. ASB 92-63-034 Basic Issue, dated March 8, 2012, by a technician certified to non-destructive testing Level II or greater is an optional terminating action for the inspection requirements of this AD.
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
