An Ontario college is in mourning after two students and an instructor were killed when a training aircraft crashed northeast of Toronto.

Durham Regional Police said three people were killed when a single-engine, four-seat Beech 33 aircraft crashed in a field near Highway 407 in north Pickering, Thursday evening.

The plane is one of five used for training purposes by Seneca College's School of Aviation and Flight Technology.

Seneca College released the names of those who perished "at the request of the families of the deceased," according to a statement.

Azizullah Yoosufani, a 26-year-old flight instructor from Toronto, was killed in the crash Thursday evening along with Students Cynthia Tsang, 20, of Toronto, and Lloyd Cripps, 20, of Brampton.

Yoosufani's brother Farman said he was in "half-denial, kind of accepting it on and off, just trying to be strong for the rest of the family."

"It's a tough time for all," Farman Yoosufani said, adding that his brother had been planning to hold a wedding reception next month.

Azizullah Yoosufani graduated with honours from Seneca's flight program in 2008 and became a flight instructor shortly afterwards. He was highly respected by faculty and his peers, who lauded his professionalism and skill.

"He was a great role model for other students. He had a very strong work ethic; he was kind and thoughtful," Adel Labib, a professor at Seneca's School of Aviation and Flight Technology, said in a statement. "He was a decent person with the full meaning of the word."

Tsang, a former Royal Canadian Air Cadet, was described as an enthusiastic and dedicated class leader who had made the President's Honour List.

A friend told CTV News that her family was devastated and wanted to grieve privately.

"She was important to all of us, an amazing person, I can't believe she's gone," said Hugo Chan. "She had her whole life ahead of her. She's a positive person; she was a great Cadet leader … (it is a) tragic loss for us."

Tsang was scheduled to graduate from Seneca College's Aviation program in 2012.

Cripps, a Canadian and British citizen, was working toward his instructor's rating and was planning on flying in Europe after he graduated.

His father, Andrew, said he had an incredible passion for flying.

"His big dream was to be a pilot, purely and simply," Andrew Cripps said. "He enjoyed flying."

Seneca President David Agnew described the crash "a tremendous loss" to the college and said the aviation community has reached out to offer their support.

"Our hearts are with the family affected and we are coming together to support the students, the faculty and the staff who have lost friends and colleagues," he told reporters on Friday.

Students gathered at the airport on Friday afternoon for an informal memorial, many of them teary-eyed.

The school's flags were flown at half-staff Friday, and a number of campus activities scheduled for next week have been cancelled.

A private memorial is being arranged for next week.

Investigators continue to probe the cause of the crash, in which the aircraft disappeared off the radar screen at Toronto's Pearson International Airport.

Peter Machete of the Transportation Safety Board of Canada, said they have determined the flaps on the plane's wings were up at the time of impact, suggesting the pilot had not been trying to execute an emergency landing.

The plane was returning to Buttonville Airport when it lost contact with air control crews.

It hit the ground at a steep angle and at a high velocity, Machete said.

Police and emergency crews descended on the scene Thursday night, after a search helicopter discovered the crash site at about 7 p.m.

Search crews found the wreckage scattered across a field. Later, an air ambulance crew found that three people had died in the crash.

"It is just devastating," Durham Regional Police Insp. Jamie Grant told reporters at the scene. "It is just unbelievable how much carnage there is there. It is a sad sight. It is sad to see that three young people have lost their lives, in this tragic accident."

The Transportation Safety Board is looking into what caused the fatal crash.

Seneca College has five Beech 33 aircrafts registered, according to the Canadian Civil Aircraft Register.

The plane involved in the crash made an emergency landing on a U.S. interstate in September, 2008 after suffering an engine failure. It was also involved in an emergency landing at Waterloo airport in 2009.

With a report from CTV's Michelle Dube