A preliminary U.S. investigation has revealed a chain of communication breakdowns and missed warnings before a deadly collision between an Air Canada regional jet and an airport fire truck at LaGuardia Airport that killed both pilots and injured dozens.The March 22 crash involved Jazz Aviation flight 646, operating as Air Canada flight 8646 from Montreal, which struck a rescue vehicle while landing on runway 4 shortly before midnight. The aircraft, a Mitsubishi CRJ-900, was heavily damaged in the impact.According to the National Transportation Safety Board’s initial report, the captain and first officer were killed, while 6 people suffered serious injuries and 33 others were hurt. In total, 39 passengers and crew were taken to hospital.Investigators say the aircraft had been cleared to land and was on final approach when multiple airport rescue vehicles were dispatched to a separate emergency near terminal B. The convoy, including the truck involved in the crash, was instructed to cross the same runway the aircraft was about to use.Audio and flight data show the fire truck crew requested permission to cross runway 4 just as the plane descended to roughly 130 feet above ground and was less than a quarter mile from touchdown. Air traffic control granted the crossing clearance moments before the situation deteriorated.Seconds later, controllers ordered the truck to stop as the approaching jet closed in. The vehicle continued forward, accelerating toward the runway despite repeated radio calls to halt..The aircraft touched down at high speed and began braking, but within seconds collided with the truck as it entered the runway. Data shows the jet was still travelling at more than 100 knots just before impact.Investigators noted that runway warning systems, including red entrance lights designed to signal approaching aircraft, were active before the crash but turned off seconds before the collision as part of normal sequencing.The report also found that the airport’s surface detection system failed to generate an alert warning controllers of the impending conflict. Officials said the system struggled to track multiple emergency vehicles because they were not equipped with transponders, preventing accurate identification and prediction of their movements.Cockpit recordings and interviews indicate confusion in the final moments. Fire crew members reported hearing urgent “stop” calls but were initially unsure who they were directed at. The truck entered the runway as the aircraft bore down.The plane came to rest heavily damaged with severe destruction concentrated in the forward fuselage. The cockpit area was crushed, while most passenger seating remained intact, likely reducing the number of fatalities.Passengers evacuated through overwing exits as emergency crews redirected from the original call to assist at the crash site.The flight crew had been on the final leg of a three-flight sequence that day, while the air traffic controller handling the runway had been on position for less than an hour but was also managing additional communications tied to the earlier emergency..Weather conditions at the time included light rain, reduced visibility and a wet runway, though officials said conditions still met visual flight rules.The Transportation Safety Board of Canada has joined the investigation, along with U.S. regulators and multiple aviation organizations, as authorities continue to examine the sequence of events, equipment limitations and human factors that led to the fatal runway incursion.The findings remain preliminary and subject to change as investigators analyze cockpit recordings, radar data and vehicle systems in the months ahead.