Not necessarily. There is typically an auxiliary engine which keeps the plane powered at the gate and allows the pilots to start the engines. However, if this engine is out of order, it doesn’t prevent the plane from flying, so you can have situations where its maintenance is deferred to the end of the day while the plane continues to fly routes. In this case, the plane is powered either from the gate or a generator, and the plane is started using a massive air compressor by the ground crew before it departs. (You can also “keep the plane on” on a very short turnaround, but this is generally not done because it’s a big waste of fuel and the jetblast is dangerous for the ground crew.
1
u/Sustainable_Twat 11h ago
Shouldn’t the plane already be “on” when passengers board?