Most military jets can be hot refueled on the ground, with engine(s) running. Some fighter jets (F/A-18s etc) can hot swap crew on the ground, with one engine r

Most military jets can be hot refueled on the ground, with engine(s) running. Some fighter jets (F/A-18s etc) can hot swap crew on the ground, with one engine running. With the F-35 and other jets, its possible to swap crew and perform minor maintenance with the jet electrically powered up and cooled with auxiliary air supply, although the engine is shutdown and then restarted. This actually saves significant time on the pre-takeoff procedures. I would think the Lockheed Martin engineers could also perform diagnostics after a failure, without interrupting power or restarting the sub-system.