Altimetry clarification
Dick has suggested that clarification of the altimetry question would be helpful, and has provided such, so here goes:
The crash site was at 4050 feet above mean sea level. The aircraft were flying on the Regional pressure setting of 1003mb. The QNH (Met Office) of the crash site was given as 1014 mb.
There are now 2 ways of viewing the happenings. If the F15s were level at a cockpit-indicated altitude of 4000 feet they would in reality be at 4300 feet above mean sea level and could not have hit the ground at the crash site.
Another way of looking at it, which supports our supposition that the aircraft were already flying low level in visual contact with the surface, is that, to impact the ground at 4050 feet AMSL, the cockpit indications of the altimeters would give a reading of 3700 feet. Not forgetting that both aircraft impacted in level flight.