British Defence Secretary Mr Geoff Hoon yesterday said pilot error was the only "plausible explanation" for the 1994 Chinook helicopter crash on the Mull of Kintyre.
Publishing the government's detailed response to a House of Lords select committee inquiry into the accident, he said there was no basis for posthumously exonerating the pilots, Flight Lieut Jonathan Tapper and Flight Lieut Richard Cook.
The decision was another blow to the families of the men who have mounted a campaign to clear their names.
In a Commons statement, Mr Hoon said reviewing the facts had been one of the hardest duties he had had to perform as a minister.
All 29 people on board the helicopter, including many of North's top security and intelligence figures, were killed when it crashed into the island in thick fog. The Ministry of Defence document rejected claims that the accident could have been caused by some mechanical failure.
While it said there could be no "cast-iron certainty" about what happened, it said it was clear the pilots had not adopted the correct procedures when they approached the island in bad weather.
"What is clear is that at some point the aircraft entered the cloud, which the pilots had been warned to expect, and that it did so well below safety altitude, at high speed and heading for high ground," it said.
It continued: "The finding of negligence is accordingly based on the incontrovertible fact that they failed to take avoiding action and, despite detailed analysis, the Ministry of Defence can find no other plausible explanation."