A small aircraft carrying a load of donated blood was in the wake of an Air Canada Airbus jet when it plunged to the ground and exploded near Vancouver International Airport this week, leading investigators to the theory that the crash was caused by the phenomenon of wake turbulence.
An official with the Transportation Safety Board said Friday that the agency will follow all possible scenarios to find a cause for the Thursday night crash that killed two pilots, but that turbulence from the larger jet is one notable option at this early stage in the investigation.
“The aircraft was in trail of a heavier aircraft and all aircraft generate vortices known as wake turbulence and the process of our investigation will look into that and see if it's a plausible scenario, and a cause of this accident,” Bill Yearwood, a regional aviation manager with the board, told a news conference.
Blocks away, pieces of the twin-engine Piper Navajo were being collected from a car-transmission parking lot up the street from an IKEA store. RCMP said it was too early to identify the pilots, staff from Richmond-based Canadian Air Charters, who were killed in the crash.
There were no injuries on the ground at the time of the crash, about five kilometres from Vancouver airport, located in the city of Richmond.
The board spokesman said they did not have any information about the experience of the two male pilots nor any reports that the pilots mentioned any other problems as they arrived in the Lower Mainland around 10 p.m. to deliver donated blood on behalf of Canadian Blood Services clinics held in Nanaimo and the Victoria-area community of Sooke.
“The weather conditions, we know, were somewhat ideal except that it was dark,” said Mr. Yearwood.
There is no black box recorder to assist with a probe expected to take months, but there is good witness information, said Mr. Yearwood, who noted that radar data has been gathered to plot the aircraft to an altitude of 213 metres.
He said the smaller plane turned into a path about three kilometres behind the Air Canada Airbus 321 jet.
“That, in itself, is a situation that warrants the question so we will look at that very closely,” he said of the wake-turbulence scenario.
There are standards for separation between aircraft to deal with wake turbulence, said Mr. Yearwood, and he said the investigation will consider whether these standards were followed.
Wake turbulence forms behind an aircraft as it flies, and takes various forms depending on where the aircraft is in its flight. It has been linked to several crashes over the years, including the November, 2001, crash of an American Airlines jet that plunged into a Queens, New York neighbourhood after takeoff from John F. Kennedy International Airport when it crossed the wake of a Japan Airlines Boeing 747.
In January, 2008, wake turbulence was linked to an incident in which an Air Canada Airbus A319, en route from Victoria to Toronto, became caught in the wake of a 747 over northern Washington state. The Air Canada jet plunged thousands of metres, rolling from side to side. Ten passengers aboard the jet were injured.
Boeing 747s have been known for their powerful wake. Fully loaded, the large jets can weigh about six times as much as the Airbus involved in the 2008 incident.
Mr. Yearwood compared wake-turbulence to “little tornadoes” that come off the wings of an aircraft “much like the wake of a boat in the water.”
“Pilots try to avoid, at all costs, flying into wake turbulence of other aircraft. If they encounter it, it's uncomfortable for the passengers, etc. It creates a rough ride,” he said.
Mr. Yearwood said there was no information to confirm media reports that the plane was on fire before impact.
The two pilots of the plane were remembered as “great pilots and solid individuals” by Mark Wilcox, operations manager for Canadian Air Charters.
“They were friends of mine,” said Mr. Wilcox, who declined to identify the men or the age of their aircraft.
“We're co-operating with the Transportation Safety Board to get to the bottom of [the accident].”
Canadian Air Charters is described as having a combined 40 years of aviation experience.
Angie Gaddy, spokesperson for the B.C. and Yukon regional operations of the Canadian Blood Services, said her organization has used Canadian Air Charters for three years as part of a distribution system that moves blood products in the region.
She said the aircraft was being used to deliver blood collected on Vancouver Island, part of a routine that involves two to three flights per week. There were a total 143 units, each equalling 455 millilitres of whole blood donations on the aircraft. The donations were collected at clinics in Nanaimo and the Victoria-area community of Sooke.
Ms. Gaddy said the tragedy will not affect the supply of blood products as her organization can draw blood from other national sources as required.
This is the second fatal air crash in Richmond in the last two years. In October, 2007, a small plane rammed into the ninth floor of a Richmond apartment building, killing the pilot and injuring two people in the apartment building.
A plane, carrying blood donations, crashed in Richmond, British Columbia, Canada on Thursday night. The plane, a twin engine PA-31 Piper Navajo departed from Victoria, when it nosedived into a parking lot during its final approach to Vancouver International Airport shortly after 10:00 p.m. PDT (UTC-7). 

Witnesses report the plane flying unusually low prior to it crashing and bursting into flames by Bridgeport Road, behind a large Ikea store.

"The plane engine sounded real low, it came almost straight down," according to ''The Vancouver Sun'' who asked witness Darren Van Leeuwen. "The flames shot up 100 feet or more."

Both of the pilots on-board were killed, it not yet known if there were any other passengers. Royal Canadian Mounted Police Assistant Commissioner Peter German stated that it was very lucky that nobody on the ground was killed.

The cause of the crash is under federal investigation.