Is it possible to start an aircraft with the master switch off?

Question

Thanks. Just wondering.

Answer 1

Absolutely! It is quite complicated, but in many numbers of ways it can. One common way is when an engine is hand-cranked on piston aircraft. This is an extreme danger, for when line refuelers like myself, or mechanics who work on airplanes, must be very caution around the propeller. One-fourth of a crank will set it to snap, and if that snap is powerful enough, you have a live engine!

Answer 2

My little old Aeronca doesn't have an electrical system, so it doesn't have a master switch.

Those that do have electrical systems require the master switch on to run the starter, but unless the engine is too big to hand-prop, you can start it by hand-propping it.

None of the electronics will work.

Answer 3

Sure as long as the master doesn't control the magnetos. If you can get the mags on she'll start. Be careful hand proping her though.

Answer 4

depends on the aircraft.  we just had a lengthy discussion about the viabilty of various disabling devices, and decided that most are more dangerous than beneficial

Answer 5

Yes.  I won't go into the details, but the engine ignition systems on piston airplanes are independent from the electrical systems.  Many planes don't even have an electrical system or master switch.