Description

On 7 February 2011, a Bombardier DHC8-100 being operated by Air Inuit on a scheduled domestic passenger flight in day Visual Meteorological Conditions (VMC) from La Grande-Rivière north to Puvirnituq failed to maintain its cleared flight level and descended without pilot awareness towards a DHC8-300 also being operated by Air Inuit on a positioning flight in exactly the opposite direction, from Puvirnituq south to La Grande-Rivière at a cleared level 1000 feet below. Co-ordinated Airborne Collision Avoidance System (ACAS) RAs alerted the flight crews to the potential conflict but both pilots acting as PF initially reacted by making turns rather than by following their RAs. Once the RAs were followed, adequate separation was achieved. None of the respective 31 and 3 occupants were injured.

Investigation

An Investigation was carried out by the TSB. The FDRs were downloaded but the limited parameters recorded meant that the data available as a result was of little assistance. Both 30 minute CVRs were overwritten and it appears that neither TCAS unit non volatile memory (NVM) record was read, although there is no explanation of why this useful and simple action was not taken.

All four pilots involved were noted to have been experienced overall in proportion to their rank but both pilots operating the southbound aircraft had low DHC8 type experience, although not so low as to preclude pairing.