The last time anyone heard from the well-known aviator and his two young American passengers, geologists Doug Thorpe and A. Kunes, they were flying out from Bristol Lake on skis near the Arctic Ocean on June 9, 1964, to Itchen Lake, which straddles the present day Nunavut-NWT border about 585 kilometres northeast of Yellowknife.
On Aug. 3, a helicopter crew flying for Ashton Mining came across an aged wreck on land not far from Itchen. There they found human remains and a wallet which identified McAvoy as its owner.
The search for McAvoy's plane went on for the better part of the summer of 1964, with members of the Royal Canadian Air Force search and rescue and numerous local pilots taking part.
At one point the search was called off, but efforts resumed after the Canadian government came under pressure from the employer of the two geologists, Roberts Mining Corporation. Two American Albatross amphibious aircraft and a full complement of U.S. soldiers scoured the Barrenlands for weeks, but nothing ever turned up.
It was later assumed that the plane must have crashed and sunk to the bottom of one of the North's countless lakes.
The fate of McAvoy and his missing plane became the stuff of Northern legend.
Psychic to the rescue?
Ken Weaver, whose family were close neighbours and friends of McAvoy and his wife Gwen and her two children, said the gregarious pilot had always claimed if he were to crash he would never be found again.
After all these years, he never doubted it.
"They even had a psychic and took a piece of his clothing to try and locate him," said Weaver.
"It was a bad feeling because everybody figured if he was down alive he was the kind of guy that would survive. But as time went on, there was such an extensive search done that people finally realized he wasn't coming home."
Weaver remembers him as a friendly man with a bellowing laugh and a penchant for moccasins, which he always wore -- on the ground or in the air. He also recalls venturing out on a family trip to go fishing one summer on the very plane McAvoy perished in.
McAvoy fit well into the age-old "fly by the seat of your pants" bush pilot stereotype, said Weaver.
On one occasion, he nearly went over Nahanni River's Virginia Falls before he was able to start up his float plane engine with barely a second to spare.
His brother, Jim, a legendary pilot in his own right, was in partnership with McAvoy during the 1950s and early 1960s. Jim said he figured McAvoy and his reckless ways would spell misfortune one day.
"We didn't part on very good terms," said Jim McAvoy.
"I told him he would kill himself... and he lasted 15 months longer. The writing was plain on the wall."
Willy Laserich, an experienced pilot and friend who took over his route after he went missing and participated in the search, said while McAvoy was an "aggressive" flyer, he was one of the best the North had ever seen.
"He got the job done that nobody else did," said Laserich.
"When I was flying for that mining company (Roberts), I had to pull up my socks to really measure up because they were used to it from Chuck. And to top it off, I had better equipment so it was easier."
Now, after nearly 40 years, the only mystery that remains is how McAvoy's ill-fated flight went wrong.