Associated links (A15Q0120)
Kathy Fox
Chair, Transportation Safety Board of Canada
Québec, Quebe, 7 September 2017
Check against delivery.
Kathy Fox
Good morning,
On the morning of August 23, 2015, a de Havilland DHC-2 float plane, better known as a "Beaver," carrying a pilot and five passengers, took off from the waters of Lake Long, near Tadoussac, Quebec. The sun was shining, the skies were clear and the winds were light. In short, it was a perfect day for a 20-minute sightseeing flight.
However, tragedy struck when the pilot made a low-altitude turn to give the passengers a better view of some wildlife. An aerodynamic stall occurred, causing the aircraft to enter a spin. The aircraft struck the ground and was consumed by fire that erupted after impact, killing the six occupants.
Today, the Transportation Safety Board of Canada is issuing a recommendation intended to prevent this type of accident from happening again. We are calling on Transport Canada to require that all commercially operated Beavers be equipped with a stall warning system to alert pilots before their aircraft stalls.
But first, let me explain how and why things went so wrong that morning, and the reasons behind our recommendation.
The pilot had already carried out three sightseeing flights that morning, each lasting approximately 20 minutes: first, over the Saguenay marine park—where whale-watching is a popular activity—and then outside the park, to observe wildlife. The pilot initially climbed to 2,000 feet, the minimum altitude required when flying over the marine park. Once beyond the marine park, he gradually descended in order to give the passengers a better view of the wildlife.
The flight was nearly over, and the Beaver was approaching Lake Long in order to land on the water. While flying at approximately 110 feet above a hill, the pilot made a steep turn to the left to show some wildlife to the passengers. During that turn, the lower wing of the aircraft exceeded its critical angle of attack, which caused an aerodynamic stall, and then the aircraft started to spin.
An aerodynamic stall occurs when the wings of an aircraft fail to generate enough lift, and—if one wing stalls before the other—a spin ensues. In a spin, the aircraft is rotating and descending vertically. A spin in itself does not necessarily result in an accident, if it occurs at sufficient altitude for the pilot to be able to regain control of the aircraft. In this case, although the pilot managed to stop the spin, there was insufficient altitude for him to prevent the aircraft from hitting the ground.
The Beaver, an iconic Canadian aircraft that was certified in 1948, was specially designed as a bush plane. Nowadays, hundreds of Beavers are used around the country, including over 200 for commercial operations.
It's important to understand that low-altitude maneuvers are part and parcel of bush flying, used to reach lakes in mountainous regions. However, these low-altitude maneuvers are not necessary for sightseeing flights.
The investigation determined that the pilot had been regularly performing low-altitude maneuvers during his sightseeing flights. However, given that the aircraft was not equipped with a flight recorder, the company was not aware of this, as it had no way of monitoring these practices.
The TSB has previously drawn attention to this problem. In 2013, the Board recommended that Transport Canada facilitate the installation of lightweight flight data recorders to help companies monitor how their aircraft are being flown. In addition, following an accident, access to this data would give investigators a better understanding of what happened.
In this accident, the aircraft had no stall-warning system. Despite the pilot's considerable experience, and even though he was a Beaver instructor, he did not perceive that a stall was imminent when he made the turn.
Since 1998, there have been 13 accidents of this type in Canada, including the accident we are discussing today, which have cost the lives of 37 people.
Even though Transport Canada and Viking, the current manufacturer of the aircraft, have recommended the installation of stall warning systems, they are not mandatory, and few companies have installed them voluntarily. It is time for this to change.
That is why, today, the TSB is recommending that Transport Canada require all commercially operated Beavers to be equipped with a stall-warning system.
This will give pilots and passengers a last defence against this type of loss of control.
Thank you.