you have no idea as to what actually caused the crash
The crash was caused by the pilots flying the aircraft into the ground. There is no dispute about that fact.
Safety Altitude is that which will keep you not less than 1000 feet above terrain five miles either side of track or ahead of you.
That all depends on which regulation you are consulting. You also need to bear in mind that the Safety Altitude over the sea is 1000' depending on how far from the coast you are.