>>2059601Not quite, unless there's a specific aircraft/operator I haven't heard of, if the APU is fully functional, you'll start all motors off the APU bleed. The APUs are always turning 100% RPM for the generator frequency and max bleed pressure, where most engines have to increase above idle power to provide enough crossbleed to start another motor. Compounding this is that jet engines at idle always burn more fuel than the APU, jetblast risks of standing up a thrust lever on the ground, and the difficulty and risk of a crossbleed start while taxiing with an engine stuck at partial thrust, as opposed to just running the bleed from the APU.
idk how a potential starter defect would be relevant, but UPS MD11 procedure is to always reach max motoring speed before introducing fuel. I'd guess max motoring for them is something like Boeings, which is less than 1% N2 rise in 5 seconds.
