AD FAA-2016-6640

We propose to adopt a new airworthiness directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters. This proposed AD would require altering the fire bottle inertia switch wiring and performing a cartridge functional test of the fire extinguishing system. This proposed AD is prompted by the inadvertent tripping of inertia-switches that has led to unintentional discharging of the fire bottles, leaving the helicopter's auxiliary power unit and engines without fire protection. The proposed actions are intended to prevent unintentional and undetected fire bottle discharges and subsequent unavailability of fire suppression in case of a fire.