TORONTO -- As investigators try to determine what caused a Canadian military helicopter to crash, retired vice-admiral and the former vice chief of the defence staff Mark Norman believes the reason could be one of two possible scenarios.

In an interview with CTV's Question Period on Sunday, Norman said the crash was likely caused by either a mechanical issue or human error.

"Fundamentally, something like this happens because there's a bizarre environmental situation, there's some sort of mechanical problem, there's human factors or some sort of military action, and [military action] doesn't seem to be the case in this situation," Norman said.

"We've had reports that the weather has been very good -- and it was at the time of the incident -- so I think we're down to two possible scenarios: some sort of mechanical issue or some sort of human factor issue."

The military Cyclone helicopter crash took the lives of six military personnel when it went down Wednesday in the Mediterranean Sea as it was returning to HMCS Fredericton.

The helicopter was part of the Fredericton's NATO mission and went down while concluding a training exercise.

Former senior Canadian Armed Forces officers say images from the area show the debris field of the crash is not large and the oil slick isn't widely spread out, suggesting the helicopter struck the waters with sudden and massive velocity.

Norman said he does not think the crash was caused by a lack of training from its crew.

"It really is too early to speculate and I don't think people should be thinking that this was a training issue per se. These crews are exceptionally well-trained. They have a lot of experience, and our military goes to great lengths to ensure that when we deploy an asset such as this on an operational mission that everybody is as absolutely prepared as they can be, so I don't think that's an issue," Norman said.

Despite the crash, Norman said he and the military have confidence in the Cyclone helicopter.

"I think it's a great aircraft but we need to remember [it's] a very complicated aircraft -- not just the back-end, the mission system, but also the avionics themselves and the flying of the aircraft," Norman said. "This is 21st-century fly-by-wire technology, and that in and of itself is going to make the investigation difficult, because they're going to have to look at a lot of the technical data associated with the different modes that the aircraft may or may not have been in at the time of the accident."

The Canadian military began using the Cyclone helicopters for training purposes in 2015, after more than a decade of expensive delays with the manufacturer Sikorsky. It wasn't until 2018 that the military began using them in real missions.

The military was supposed to have received 28 Cyclones from Sikorsky in November 2008, but to date has only received 18. In 2012, then-defence minister Peter MacKay called it "the worst procurement in history."

"It's important that we not try and conflate, the history of the procurement with the capability of the platform itself," Norman said. "MacKay may well have been right, but that doesn't mean that it's not an exceptional piece of equipment, and that it has the full confidence of those people who have been flying it up to this moment."

All of the military's Cyclone helicopters have been grounded while a flight investigation team works in the region to determine the cause of the crash. The Cyclone's flight-data and voice recorders have been recovered and will soon be returned to Canada for analysis.

"Unfortunately, these types of things do happen, and the military will take a very measured, deliberate and facts based approach to this, and if there's something to learn from the investigation they want those lessons immediately," Norman said.

"That's really one of the fundamental reasons why they go to the lengths they do to do the investigation; not just to find out what happened but to ensure that if it is something where they can change procedure then they'll do so."

With files from The Canadian Press