The cause of a chairlift crash at a Kelowna ski resort on Saturday is being investigated by the B.C. Safety Authority. 

Paul Gervais said he took his eight-year-old son skiing for the first time last month, and remembers telling him the chairlift was perfectly safe.

"I'm the dad that, you know, three weeks ago my son got on his first chairlift and I said, 'Don't worry, these things never crash,'" said Gervais.

But on Saturday morning, as Gervais and his son sat on a chairlift at Crystal Mountain ski resort, that's exactly what happened. A chairlift cable came loose around 11 a.m. PT on Saturday — possibly when an empty chair hit a ski tower — causing chairs to fall about six or seven metres to the ground. Four people were injured, including two critically.

Gervais says he and his son were tossed up in their seats when chairlift cable came loose.

"He says, 'Dad, 'Dad I'm slipping.' ... I just got him to hold on to his arm rest, I hung on to mine, and with my free arm I just kind of put my hand underneath him and held on to him," said Gervais.

Gervais said the plastic seat shattered underneath them, and the two were left clinging to rails. 

"I went to brace myself with my right arm with my seat. There was no seat. And I looked down to the ground and our seat was 25 feet below us in pieces."

He said he escaped with bruises on his arms, back, and buttocks. 

"You know we got pretty beat up for just, still staying in a chair. And it's a pretty traumatic thing for an 8-year-old to go through. And I hope he never has to go through that again."

One of the oldest chairlifts in B.C

It was not the first time there has been an accident on the Crystal Mountain chairlift. The B.C. Safety Authority was called in last year too.

"There was an incident in early 2013 that led to us issuing a safety order, but there were no injuries as part of that," said B.C. Safety Authority spokesperson Quinn Newcomb.  

When asked what the incident was, Newcomb said "I can't get into that."

The ski resort's chairlift system was built in 1967, and is one of the oldest in the province. It is inspected every year — the last of which was performed three months ago. 

Now Gervais is wondering what went wrong.

"I kept hearing, it hasn't broke down in 60 years," he said.

'Quite rare for a chairlift to malfunction'

The resort has been closed since the accident, as safety officers try to determine what happened.

"It's quite rare for a chairlift to malfunction. The vast majority of incidents that come to our attention are from user error, normally when people are loading or offloading off the lifts," said Newcomb.

The chairlift does have two fail-safe mechanisms, one of which appears to have worked and the other of which appears to have failed.

The last time an equipment malfunction led to a serious chairlift accident leading to death or injury in B.C. may have been in 1995. Two people died and nine were injured when a chairlift cable came loose from its track in Whistler. 

A coroner's report found the accident could have been prevented. 

Newcomb insists chairlifts are very safe. 

"Skiers who use them should feel very confident," he said.

That may be so. But Gervais said it could be a while before he takes his son back up a mountain.

"I'm going to let him be the one that says, 'Hey dad, why don't we go skiing this weekend.' And we'll take it from there.

With files from CBC's Brady Strachan and Deborah Goble