Airworthiness Directive · Amendment 39-18173 · Main rotor gearbox
Sikorsky Aircraft Corporation (Sikorsky) Model Helicopters
This AD applies to Model S-92A helicopters, serial number (S/N) 920006 through 920179, certificated in any category.
We are adopting a new airworthiness directive (AD) for Sikorsky Model S-92A helicopters. This AD requires installing a main gearbox (MGB) failed pump sensor and vacuum switch wiring, installing an MGB oil auto bypass system, activating Aircraft Management System (AMS) 7.1 software to show a new visual warning, and installing updated enhanced ground proximity warning system (EGPWS) software that includes an aural annunciation of a complete oil pressure loss condition. This AD also requires inserting a Rotorcraft Flight Manual (RFM) Supplement into the applicable RFM. This AD was prompted by investigation results of in- service oil leakage incidents. The actions are intended to alert and prevent MGB oil loss, which could lead to 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 500 hours time-in-service:
(1) Insert a copy of the Sikorsky S-92A Rotorcraft Flight Manual (RFM) Supplement No. 45, Part I, dated July 30, 2012, into the RFM.
(2) For helicopters with S/N 920006 through 920132:
(i) Install an MGB failed pump sensor, Modification Kit Part Number (P/N) 92070-35007-011.
(ii) Install MGB vacuum switch wiring, Modification Kit P/N 92070-55039-013.
(3) For helicopters with S/N 920006 through 920179:
(i) Install an MGB auto bypass system, Modification Kit P/N 92070-55061-011.
(ii) Activate Aircraft Management System 7.1 software to show a new MGB “OIL OUT” visual warning.
(iii) Install enhanced ground proximity warning system software version 030.
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
