One of my earliest pals in aviation lost his life in a Westwind that plunged into the water after departing Sydney in the late 70s.
The reason: a circuit breaker pulled by the training Capt. on a line check. A subsequent further failure rendered the situation irrecoverable.
Google it and read it for yourself. The real tragedy was that the trainer had a history of such stunts, was known for it, and was left to his own (stupid) devices. If he'd been "given correct guidance" my mate O*** would b e here today
www.atsb.com.au/publications/investigation_reports/1985/aair/pdf/198502557.pdf