An investigation into a fiery plane crash in Richmond that killed two pilots and injured seven passengers has found the pilot lost control of the plane moments before the crash, but there was no loss of power or mechanical failure.

The Transportation Safety Board issued its interim report on Thursday into the crash which happened last October when the small passenger plane was attempting to make an emergency landing shortly after takeoff from Vancouver's airport.

The TSB said the pilot aboard the ill-fated passenger plane lost control less than 100 metres above the ground and by the time he righted the plane, it was too late. The board concluded the pilot was in the process of recovering control when the plane crashed.

"Certainly a couple more hundred feet (in altitude) might have given him enough room," said lead investigator Bill Yearwood.

"He did recover the roll and had pulled the nose up partially."

The twin-engine plane was returning to Vancouver's airport because of an oil leak, but Yearwood said investigators don't believe there was anything mechanically wrong with the Beechcraft King Air 100.

"We know that they didn't declare an emergency and we know that they declined emergency equipment on approach."

Fire caused deaths of pilots

The TSB's report concluded those most seriously hurt after the Northern Thunderbird Air flight crashed were injured most by the fire that engulfed the aircraft after the crash.

Drivers stopped at a red light were among those that helped the passengers escape the burning plane.

The two pilots died in hospital and while all seven passengers escaped, at least one was badly injured and is still recovering.

The TSB progress report said the Richmond, B.C., fire crew pulled the seventh passenger out of the wreck, but there was some confusion about the total number of people on board and how many pilots were in the cockpit.

Yearwood said the passengers were very fortunate that one man had paid close attention to the passenger briefing about escaping a plane.

"After several attempts he was able to open the door and from there he helped one passenger and passersby helped the others except for one."

Fire was visible from the right side of the plane making the left rear the only exit, the report said.

"The door frame was deformed and the door was jammed shut. An able passenger opened it with difficulty."

Yearwood met with several of those passengers on Wednesday to explain what investigators had learned so far about the cause of the crash. He said all the passengers are recovering.

"The last passenger to be retrieved suffered the most serious injuries and has had to have several operations, but he was able to come and visit and is walking around."

2006 recommendations ignored

The TSB noted in the report that it has been recommending changes in aircraft design to prevent post-crash fires since 2006.

However, the board notes that aviation regulators around the world have also ignored taking measures to ensure post-crash safety from fire.

"The responses from regulators on these recommendations are unsatisfactory," the board said in its latest report.

"Our investigations in the past have indicted there's room for improvement in design," said Yearwood.

"It's always hard when we see another one of these accidents after we've identified a problem."