There's a bitter irony in the latest rumour - that Anthony was flying John up to Lake Michaelson (@13,000') to photograph old plane wrecks on the mountain.
At the moment with the current really hot weather we're having, there is a LOT of turbulence even at lower altitudes - never mind on the side of a mountain. At that sort of altitude there would not be a lot of performance left in the Foxbat in order to fly away from any bumps/downdrafts etc. Otherwise I am sure they would have just put down somewhere (even if far from ideal) and survived the crash.
Its very sad this happened. Mt Kenya has claimed a lot of planes/pilots/passengers over the years.