The pilot said he believed the machine's controls had jammed - forcing the giant helicopter into a head-on collision course with the Mull. He considered the board of inquiry findings - that the Chinook pilot had chosen the wrong rate of climb - as "unlikely in the extreme".
The pilot, who cannot be named on security grounds, put forward his theory when he appeared as a witness for the family of Flight Lieutenant Jonathan Tapper, the captain of the helicopter involved, at the fatal accident inquiry in Paisley, Strathclyde.
He and another Chinook pilot told the inquiry that Flt Lt Tapper - and most other Chinook pilots - had repeatedly expressed concerns about the new Mk II Chinook. Flt Lt Tapper was said to have voiced concerns "on a daily basis" that it was less capable of doing the job than the Mk 1 it replaced. The RAF board of inquiry concluded the likeliest explanation for the crash - which killed the four-man RAF crew and their 25 passengers including Ulster's top anti-terrorist RUC, military and MI5 officials - was a high-speed cruising climb at a rate of climb too low to clear the Mull.
The RAF board said that although technical malfunction could not be ruled out, there was no evidence to suggest this.
Central to the evidence has been the low-level flight path the aircraft was taking. Less than a mile short of the Mull the pilot entered an updated navigation marker, or "waypoint".
In the final seconds before disaster the helicopter dramatically increased its climb rate.The change of waypoint - on the RAF board of inquiry scenario - was part of a pre-planned change from fly-by-sight rules to instrument flying rules. But the pilot said yesterday he thought it "inconceivable" that the helicopter would be that close to land, out of visual contact, and below its safety altitude.Reuse content