Pilot finally cleared over mystery of 1947 mountain plane disaster.
Intrigue surrounded the disappearance of the converted bomber Star Dust after it plummeted into a 22,000ft mountain on August 2, 1947, and there were even theories it had been sabotaged by spies.
The wreckage lay undiscovered for more than half a century until climbers stumbled across it - and the remains of three occupants which had been preserved by the sub-zero cold - in January, at the Argentina-Chile border.
Now an investigation by an Argentinian air force officer has concluded Star Dust crashed because of severe weather, and cleared pilot Capt Reginald Cook of any blame for the crash, which killed all five crew and six passengers.
A heavy snowstorm forced Capt Cook to veer off course and fly into the volcanic mountain.
"We came to the conclusion they were unable to correct their positioning because they were flying in very cloudy weather," said investigator Mr Luis Estrella, who examined wreckage brought down from the crash site 16,500ft up Mount Tupungato.
Records indicated that heavy snow had been falling for three days when the British South American Airways flight from Buenos Aires to Santiago vanished and aviation experts said the plane, which did not have de-icers, was unfit to travel in such cold weather.
But a 1948 Civil Air Accident report on the tragedy, by Air Commodore Vernon Brown, concluded the cause of the accident was "obscure", although it pointed the finger at Capt Cook.
"As this was the pilot's first trans-Andean flight in command, and in view of the weather conditions, he should not have crossed by the direct route," it read.
Yesterday Capt Cook's brother-in-law Mr John Parker, aged 78, from Melbourne, Derbyshire, said he was "delighted" the pilot had finally been cleared of any criticism.
"He was good at his job and he had been decorated many times in the war.
"I've believed from the start that such an experienced crew would not have taken any risks," said Mr Parker.
"I couldn't imagine Reggie doing a foolhardy thing like going into a pass when they had been warned the weather was bad."
The vanishing of the Avro Lancastrian - a conversion of the Lancaster bomber, famous for the Dambuster raids - was one of the murkiest chapters in British aviation history.
Star Dust's enigmatic final radio message, received in Morse code by Chilean radio operators just before the crash, was transcribed as the meaningless word "STENDEC".
No one has been able to establish what the mystery phrase meant, although other possible transcriptions suggested over the years include "SOS ICE", "URGENT" and "VALE", the Latin for farewell.
One of the passengers, Mr Paul Simpson, was a diplomatic courier, with the title King's Messenger, believed to have been carrying secret documents.
The two crashes led some to suggest that Star Dust was sabotaged - perhaps in connection with Mr Simpson's presence onboard.
Members of the Argentinian armed forces hiked up Mount Tupungato in February to recover pieces of debris that investigators used to compile their report and later returned for the bodies.