Background
The aircraft was on a scheduled domestic flight from Turnhouse Airport, Edinburgh to Heathrow Airport, London. The flight departed Edinburgh at 23:17 hours UTC on October 26. The flight was uneventful until reaching the Garston VOR holding point.
Approach Attempts
At 00:15, the captain decided to attempt a landing on runway 28R. The co-pilot was probably flying the ILS approach, monitored on PAR by the air traffic control officer, while the captain sought visual reference. The RVR on this runway was 350 m. At 00:23, the captain reported overshooting.
He then attempted runway 28L, where RVR was 500 m. ATC provided a full talkdown as the ILS operated only on glide path. At half a mile from touchdown, the PAR controller was about to instruct an overshoot when the pilot had already initiated one. At 00:35, the captain reported overshooting because they could not see anything and requested holding. The aircraft held at Garston.
At 00:46, another Vanguard landed successfully on runway 28R. At 01:11, despite no weather improvement, the captain asked to attempt runway 28R again, possibly stimulated by the other aircraft's success. Meanwhile, another Vanguard had overshot on 28R.
Final Approach
The captain started a monitored ILS approach on runway 28R at 01:18. At 01:22, the PAR controller reported the aircraft was 3/4 mile from touchdown and on centerline. Twenty-two seconds later, the captain reported overshooting.
During the overshoot, the co-pilot rotated the aircraft abruptly, and the captain raised the flaps. Instead of selecting flaps to 20 degrees, he selected 5 degrees or fully up. Speed did not build up, so the co-pilot relaxed elevator pressure. Speed increased to 137 kts with a rate of climb of 850 ft/min. The co-pilot then put the aircraft's nose further down. Four seconds before impact, the VSI indicated a substantial rate of climb and the altimeter showed a gain in height, but the aircraft was actually losing height. The co-pilot was misled into continuing the down pressure. The Vanguard entered a steep dive and struck the runway about 2600 feet from the threshold.
Probable Cause
The cause of the accident was attributed to pilot error due to the following combination of events: low visibility (less than 50 meters), tiredness, anxiety, disorientation, lack of experience of overshooting in fog, over-reliance on pressure instruments, position error in pressure instruments, lacunae in training, unsatisfactory overshoot procedure, indifferent flap selector mechanism design, and wrong flap selection.