Avionics Master Switch

A separate power switch that controls electrical power to the avionics bus, protecting radios, GPS receivers, transponders, and other sensitive electronic equipment from voltage spikes that occur during engine start. The avionics master must remain off during engine start and shutdown and is turned on only after the engine is running and the electrical system has stabilized. If the avionics master is inadvertently left on during start, the transient voltage from the starter can damage expensive avionics equipment.