Key Switch?
in 912iS Technical Questions
8 years ago
I am required by Australian law to have a means of preventing my aircraft from unauthorised use. The usual means now include a throttle lock, ignition switch with key and door locks. At my flying club we also tried a wheel clamp, but that is heavy, difficult to stow and a real nuisance.
So my question - how best to disable the engine without creating a new safety hazard in flight? A master switch with a key (contactor actuation) to disable the master contactor seems to be about the only way I can think of doing it and maintain the simple and elegant way Rotax has designed the electrical system. Even if the key switch failed in flight, I think the engine should keep running and the aircraft systems as well. With the contactor disabled I don't think it is possible to start the engine.
Of course it would be possible to dream up an arrangement of relays and a conventional ignition switch that does the same task as the Lane A, B, start and master switch functions but that generates a raft of new failure points and failure modes and is unlikely to be reliable.
So my question - how best to disable the engine without creating a new safety hazard in flight? A master switch with a key (contactor actuation) to disable the master contactor seems to be about the only way I can think of doing it and maintain the simple and elegant way Rotax has designed the electrical system. Even if the key switch failed in flight, I think the engine should keep running and the aircraft systems as well. With the contactor disabled I don't think it is possible to start the engine.
Of course it would be possible to dream up an arrangement of relays and a conventional ignition switch that does the same task as the Lane A, B, start and master switch functions but that generates a raft of new failure points and failure modes and is unlikely to be reliable.
