TSB report into fatal plane crash says aircraft may have been flying too slowly

Investigators with Canada's Transportation Safety Board say it appears a small plane was not going fast enough when it rolled and crashed into trees near the airport in Chilliwack, B.C., killing all three people on board.

A report into the October 2023 crash that killed a flight instructor and two students says investigators could not determine the specific exercise that was being conducted when the Piper PA-34-200 Seneca plane approached the airport, rolled to the right and crashed into trees behind a casino.

The report says dashcam video from a passing vehicle and the post-accident wreckage examination are consistent with the aircraft entering a "minimum control speed" roll before the crash.

The minimum control speed is "of primary importance" when an aircraft loses an engine or during a simulation of the loss of an engine, according to Todd Pezer, senior regional investigator with the Transportation Safety Board in air operations.

He said instructors teach specific manoeuvres designed to regain control of the aircraft in the case of engine loss.

If an engine is lost, it's critically important to maintain appropriate air speed so that there is "enough air flowing over your control surfaces to regain control," he said.

The risk is if the aircraft flies too slowly and there isn't enough air flowing over flight control surfaces, such as the rudder, to maintain control of the airplane, Pezer said.

"If the airplane slows down below that speed, then the control can be compromised or lost completely," he added.

But Pezer highlighted that without a cockpit voice recorder or a flight data recorder, the transportation board can't specifically say if the three on the plane were conducting related training exercises or not.

"We can observe the effects that we saw, and we can say that it looks consistent with something that would happen with the demonstration of these exercises, but we can't with confidence say for sure we know that was happening."

The report said rolls happen when there is uneven power between a plane's two engines and the aircraft's speed falls below the minimum required.

The investigation did not discover any issues with the flight controls that would have led to the loss of control, or anything mechanical that would have prevented either engine from producing power, according to the report.

The TSB is an independent agency that investigates incidents involving air, marine, pipeline and rail transportation.

The agency says its aim is to promote transport safety, rather than to find fault.