Propair Flight 420 was a scheduled airline service operated by Propair, utilizing a Beechcraft 1900D twin-engine commuter aircraft. On its final flight departing from Montréal–Mirabel International Airport, the aircraft took off bound for Baie-Comeau. Shortly after liftoff, the aircraft encountered difficulties and crashed in a farmland area near the airport. The crash occurred in the early morning hours when weather conditions were less than ideal. Reports indicate that thick fog and poor visibility were present, which may have played a critical role in the pilot's inability to maintain proper flight control. Local emergency services responded promptly to the crash site but unfortunately confirmed that none of the passengers or crew survived.The investigation that followed focused on multiple factors, including the aircraft's airworthiness, the decision-making process of the flight crew, and environmental conditions at the time of departure. The Transportation Safety Board of Canada was tasked with conducting a thorough analysis. Their findings pointed to a combination of weather challenges and possible misjudgments made during the flight, highlighting the complexities of operating regional flights in rapidly changing weather conditions. As a result, the crash spurred discussions on enhancing safety protocols for commuter flights within Canada.