One witness on the ground said she saw three aircraft at low level and described "bangs" (compressor stalls?) coming from one aircraft. So, low-level, single-engine maneuvering over mountainous terrain? If her observations were correct or not you would think the Navy would have looked at the safety record of the twin-engine T-38 and the twin-engine T-37 and the twin-engine T2C Buckeye before buying a single-engine trainer.