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The Transportation Safety Board of Canada (TSB) has released its investigation report (A17Q0030) on a collision between two flying school aircraft that occurred over St-Bruno-de-Montarville, Que., in March 2017.
The investigation determined that both pilots, who were flying solo under visual flight rules in controlled airspace, had deviated from the altitude restrictions provided by air traffic control before colliding in mid-air.
In the early afternoon of March 17, 2017, a Cessna 152 (C-GPNP), operated by a licenced pilot undergoing commercial training at Cargair Ltd., was returning to the Montréal/St-Hubert airport from a training flight in a local training area.
At the same time, another Cessna 152 (C-FGOI), operated by a Cargair Ltd. student pilot, was departing the airport for a training flight in a local training area.
At 12:38 Eastern Daylight Time, the two aircraft collided at 1,500 feet above the Promenades St-Bruno shopping mall, less than two nautical miles from the airport.
Substantially damaged, the C-GPNP aircraft subsequently struck the roof of the mall, seriously injuring its pilot. The C-FGOI aircraft, which fell in a parking lot, was destroyed and its student pilot was fatally injured.
Both pilots were international students enrolled in flight training whose first language was neither English nor French, although both had their English-language proficiency assessed as operational, meaning they met the minimum international proficiency level acceptable for radiotelephony communication.
The investigation determined that the pilot of C-GPNP inadvertently descended 100 feet below his altitude restriction of 1,600 feet while attempting to troubleshoot a radiocommunication issue.
Meanwhile, for unknown reasons, the student pilot of C-FGOI climbed 400 feet above his altitude restriction of 1,100 feet, and then collided with the other aircraft from below.
Neither pilot saw the other aircraft in time to prevent the collision, partly owing to the limitations of the see-and-avoid principle, which is the basic collision avoidance method under visual flight rules.
A pilot’s ability to visually detect another aircraft and avoid collision is affected by many factors, such as: proximity, reaction time, obstructions to field of view, pilot scanning techniques, in-flight monitoring of instruments, and radiocommunications.
The investigation also found that the density and variety of operations conducted at the St-Hubert Airport increase the complexity of air traffic control. The varying levels of flying skills and language proficiency among the student pilots of the four local flying schools add to this complexity.
In this regard, the investigation found that Transport Canada’s oversight of aviation language proficiency testing (ALPT) is limited to administrative verifications.
Therefore, it is not possible to assess whether and to what extent designated examiners administer the ALPT program in a manner that ensures validity, reliability, and standardization nationally.
After the occurrence, Transport Canada published a Civil Aviation Safety Alert recommending that flight-training units ensure that student pilots have been awarded an operational level of language proficiency in accordance with the language proficiency scale set out in the personnel licensing standards prior to their first solo flight.
The TSB is an independent agency that investigates marine, pipeline, railway and aviation transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.