The runway at New York's LaGuardia Airport where an Air Canada jet collided with a fire truck, killing both pilots and injuring dozens of others, reopened Thursday (March 26) morning, marking a significant step in the airport's recovery from one of its deadliest incidents in decades.

The Port Authority of New York and New Jersey said the tarmac resumed operations at around 10 a.m. after the runway and its supporting infrastructure were "repaired, inspected, and confirmed" to meet Federal Aviation Administration (FAA) regulations for safe operation.

The deadly crash occurred just before midnight on Sunday (March 22), when a Jazz Aviation regional jet operating on behalf of Air Canada, traveling from Montreal with more than 70 people aboard, slammed into a Port Authority fire truck that had been cleared onto the runway. Both pilots, Mackenzie Gunther and Antoine Forrest, were killed in what became the first fatal crash at LaGuardia in 34 years. About 40 passengers, crew members, and fire truck personnel were taken to hospitals. As of Tuesday (March 24), Air Canada confirmed six people remained hospitalized.

Jennifer Homendy, chair of the National Transportation Safety Board (NTSB), outlined a chilling timeline of the crash's final moments. According to investigators, one of the two air traffic controllers on duty cleared the fire truck to cross the runway just 12 seconds before the Air Canada flight touched down, when the plane was already a little more than 100 feet off the ground. Nine seconds before impact, the tower frantically ordered the fire truck to stop. Airport communications captured the controller's urgent transmission: "Stop, stop, stop, Truck 1. Stop, stop, stop."

The NTSB is now working to determine which of the airport's many layers of safety precautions failed. Investigators are examining whether two overnight controllers is sufficient for a major airport, why the runway warning system did not trigger an alarm, who was coordinating air and ground traffic, and whether the fire truck driver heard the controller's desperate warnings.

A key factor in the system's failure: the fire truck was not equipped with a transponder, which prevented the airport's advanced surface surveillance system, known as ASDE-X, from detecting the vehicle and triggering an automatic alert. LaGuardia is one of 35 major U.S. airports equipped with this type of advanced system, which is designed to track all planes and vehicles on the airport surface. As recently as May of last year, the FAA urged all 35 airports with such systems to equip their vehicles with transponders, noting that federal funding was available to help cover the cost.

Homendy said the runway's embedded status lights appeared to be working at the time of the crash. Those lights are designed to automatically turn red when a runway is occupied, warning vehicle operators not to enter, even if a controller has granted permission.

The investigation also revealed that the tower was busier than usual that night. Flight delays had more than doubled the number of late-night arrivals and departures, with a dozen flights landing in the 40 minutes before the crash. At the same time, controllers were managing an unrelated emergency involving a United Airlines jet that reported a strong odor in its cabin.

Homendy urged caution about placing blame too quickly. "I would caution against pointing fingers at controllers and saying distraction was involved," she said. "This is a heavy workload environment." She added: "We rarely, if ever, investigate a major accident where it was one failure. When something goes wrong, that means many, many things went wrong."

The airport had been operating on a single runway since Monday (March 23) afternoon, when it first resumed limited operations. About one quarter of the airport's flights were canceled Tuesday, with average delays exceeding four hours.

The NTSB continues to conduct interviews, document wreckage, and use drone footage to study the plane's approach path. Investigators are also reviewing the cockpit voice recorder, which was recovered by cutting through the aircraft's roof.

Ross Kaminsky on the News with Jeana Gondek