Summary
We propose to adopt a new airworthiness directive (AD) for certain The Cessna Aircraft Company Model 750 airplanes. This proposed AD was prompted by reports of direct current (DC) generator overvoltage events. This proposed AD would require replacing the auxiliary power unit (APU) generator control unit (GCU). We are proposing this AD to prevent DC generator overvoltage events, which could result in subsequent smoke in the cockpit and loss of avionics and electrical systems.