Am I being simplistic, but why on earth should any A/T malfunction/ unserviceability cause any aircraft to crash? All aircraft are cleared to fly with the A/T u\s. On my last type we could even carry out CATIII autolands manipulating the Thrust Levers manually.
On first sign of malfunction when airborne, disconnect and operate the Thrust Levers manually as normal. Even if required, possibly disconnect the autopilot and fly manually while you sort out the automatics. Or am I missing something?