An air traffic controller at St-Hubert airport tried to contact a 23-year-old pilot involved in Friday's deadly collision above St-Bruno four times before the crash but never received a response.

In a recording of conversations between the control tower and the aircraft, controller can be heard telling the pilot to maintain an altitude of 1,600 feet as he approached the runway. He also told the pilot another aircraft was one mile ahead of him at an altidude of 1,100 feet.

No response was given when the two aircraft collided above the junction of Route 116 and Highway 30.

The other plane was piloted by a 21-year-old who was killed after his aircraft was struck and crashed into the parking lot of the Promenade St-Bruno.

The 23-year-old's plane crashed on the mall's roof. He suffered serious injuries and is in hospital though police said the extent of his injuries is unclear.

Both planes were the same make and model of Cessna 152 aircraft, both owned by Cargair, a local flight school.

Longueuil police spokesperson Nancy Colagiacomo said that only one person was aboard each plane.

"The person who was seriously injured was a pilot, and the death was the other pilot," she said.

Two other people were taken to hospital and treated for nervous shock.

Firefighters removing fuselage from plane that crashed at promenades st Bruno pic.twitter.com/fO7UmelioZ — Rob Lurie (@RLurieCTV) March 17, 2017

Witnesses in parking lot

Rene Thibault said he was in another of the mall's parking lots when he heard a loud cracking sound. He started yelling for the people underneath the collision to watch out.

"I saw the plane spinning as it fell," he said. "There's no words for this."

Two other passersby described a similar scene: a loud noise followed by the plane spinning wildly. One witness said she was worried one of the planes was going to crash in front of the building's doors but it ended up on the roof instead.

The mall was evacuated because of a gas leak, and will remain closed on Saturday.

Prior incidents with Cargair

The Transportation Safety Board's team of investigators arrived in St-Bruno at 5:30 p.m.

Longueuil police will lead the investigation, working with experts from the TSB and Transport Canada to determine exactly what happened.

Both planes were owned by a local flight school, Cargair, and both planes were Cessna 152 aircraft.

On Friday evening Isabelle Langevin of the TSB said every piece of both planes will be examined and photographed before being shipped to its lab in Ottawa.

She added the federal agency will also talk to every witness of the crash.

The flight school said it is co-operating with the investigation and offering condolences to the deceased.

"We are concentrating our efforts to help our employees and students who are all part of the Cargair family," said Josée Prud'homme, the company's president.

Twenty years ago four people died when two Cessnas, one privately owned and the second owned by Cargair, collided at the Mascouche Airport.

In that 1997 crash both planes were approaching the runway to land.

Another Cargair pilot was involved in a near-miss incident that was investigated by the TSB in 2001.

In that case, a Cessna 172 flew from Mascouche around downtown Montreal, then came into the path of an Air Canada regional jet landing at Dorval airport.

The planes came within 200 feet of each other, but nobody was injured and neither plane was damaged.

- With files from The Canadian Press