Nine people were rushed to hospital Thursday after a small plane slammed onto a city street just outside Vancouver International Airport.

Kelsie Carwithen, with the B.C. Ambulance Service, said five patients were rushed to Vancouver General Hospital in critical condition.

She said another four patients were taken to the nearby Richmond General Hospital with injuries that are considered non-life threatening.

The plane burst into flames shortly after it crashed while attempting to return to the airport. It landed near a street just outside its fences, snarling traffic at the peak of the city's afternoon rush home.

Officials for the airport said the plane, a Beech King Air 100, is operated by Northern Thunderbird Air, based in Prince George, B.C.

The plane, which can carry up to nine passengers, was bound for Kelowna but turned around when it encountered a problem. An airport statement said the Vancouver Airport Authority went into emergency mode at 4:12 p.m. PT.

Steve Smith, from Richmond, was driving home from his daughter's volleyball game when he saw black smoke rising from the crash site.

"By the time I parked my car, there was a massive jam-up of cars. I saw people being tended to at the side of the road," he said in an interview.

Within moments he watched fire trucks scream into the area, along with airport authority vehicles.

"I was thinking, those guys are heroes for helping them out. You must go into auto-mode. You get a knot from your stomach thinking people are hurt," he said.

"It was a very heartening response."

Bill Yearwood, with the Transportation Safety Board, said there are three investigators at the crash site.

He said the plane experienced a problem, so one of its two pilots called in and it was cleared to return. The plane was about 60 kilometres northeast of the airport at the time, in the area of Golden Ears Provincial Park.

"The aircraft fell short of the runway and crash-landed on the road," he said in an interview.

He couldn't confirm what problem had been reported.

"My information at this time is they had not declared an emergency, but had requested clearance to return to the airport."

Graeme Wallace, who works at the Aviation World pilot supply store, was watching crews work on the wreckage during an interview.

"The plane's basically broken in half, as far as I can see," he said, looking about 50 metres out of his store's door. "The fire's out, the emergency people are all surrounding it doing their bit."

Wallace said he looked outside when he heard the commotion.

"It was a good size, imagine half of a small plane on fire. It's pretty big."

According to the Northern Thunderbird Air, the company was formed in 1971 and was an amalgamation of Northern Mountain and Thunderbird, two airlines from northern B.C.

The company said it has 11 aircraft and 70 employees. Calls for comment were not immediately returned.