Keystone Air is mourning the loss of one of its pilots, who died in Tuesday's plane crash in northwestern Ontario.

Fariborz Abasabady, 41, was one of the four killed in the crash in North Spirit Lake. The plane, an eight-seat Piper PA-31 Navajo, was on its landing approach when it slammed into a frozen lake and caught fire.

Winnipegger Brian Shead, 36, was the lone survivor.

Abasabady, from Lockport, Man., began working for Manitoba-based Keystone last summer, according to company spokesman George Riopka.

Everyone at Keystone is upset at the loss and hope to find answers about what caused the crash, he said.

North Spirit Lake is located in remote northwestern Ontario, near the Manitoba border. (CBC)

"Keystone is grieving … because pilots have lost you know, one of their co-workers and so they want to know as much as anybody else what happened here."

Abasabady leaves behind a widow.

Riopka said Abasabady had worked in pilot training for three years before joining Keystone and had 2,400 hours of flying time.

"He seemed to be very kind and concerned and he was excited about working for Keystone and learning to be a good charter pilot," he said.

"He was very easy to work with."

Victims from Winnipeg

The other victims include Ben Van Hoek, 62, Colette Eisinger, 39, and Martha Campbell, 38.

All were from Winnipeg save for Van Hoek, who was from Carman.

Van Hoek, Eisinger and Shead worked for Aboriginal Strategies, a Winnipeg company that provides financial management services to First Nations.

Campbell was once the health director for Nishnawbe Aski Nation, a political organization representing 49 First Nation communities across northern Ontario.

She had moved to Winnipeg four years ago but frequently returned to North Spirit Lake First Nation — one of the NAN communities — to help in the band office.

The plane had been chartered by Aboriginal Strategies.

Transportation Safety Board investigators arrived at North Spirit Lake on Wednesday afternoon to begin looking into the cause of the crash. It won't be an easy task, said TSB spokesman Peter Hildebrand.

"The wreckage is extensively damaged by fire and impact forces. It's located in a very remote location, so we're really just going to have to resort to basic investigative techniques," he said.

The investigators also hope to gain valuable information from Shead and from North Spirit Lake residents who may have seen what happened as the aircraft approached the runway, Hildebrand said.

They couldn't reach the crash site earlier because of its remote location.

Airline investigated

Transport Canada will be conducting an inspection of Keystone Air to verify compliance with aviation safety regulations, spokeswoman Glyniss Hutchings stated in an email to CBC News.

The scheduling of this inspection is currently underway.

She noted that Transport Canada suspended Keystone’s Air Operator Certificate (AOC) following an accident on June 11, 2002, and then again on February 5, 2004, following a regularly scheduled inspection.

The first suspension lasted 13 days and the second was for 18 days.

This latter suspension was "based on significant safety concerns with the company's maintenance management system," according to the federal government's website.