One of only two air traffic controllers on duty at LaGuardia Airport cleared a fire truck to cross a runway about 12 seconds before an Air Canada flight touched down, federal investigators said Tuesday, laying out a timeline that left little time to prevent a collision Sunday night. The crash killed both Air Canada pilots and left several passengers injured, according to the National Transportation Safety Board.
The NTSB said the fire truck asked to cross the same runway where the Air Canada plane would land, even though the airline had already been cleared nearly two minutes earlier. Investigators said one controller then cleared the truck to cross five seconds later, when the plane was a little more than 100 feet (30 meters) from the ground, as the aircraft came in to land.
As the aircraft closed on the runway, the NTSB said the tower told the fire truck to stop nine seconds before the collision—about a second before the plane’s landing gear touched down. Homendy said it appears the airport’s runway status lights were working, which she said might have warned the vehicle operator not to enter the runway even if the controller had approved the crossing.
Homendy said investigators are trying to determine which of the airport’s many safety layers failed and allowed the fire truck onto the runway. She said investigators are also working to understand other elements of how traffic was managed, including why a runway warning system did not alert the possibility of a crash, who was coordinating air and ground traffic, and whether the fire truck heard the controller’s last-second calls to stop.
Homendy said, “We rarely, if ever, investigate a major accident where it was one failure,” adding that when “something goes wrong, that means many, many things went wrong.” She also said she cautioned against “pointing fingers at controllers and saying distraction was involved,” describing the control environment as one with a “heavy workload.”
The NTSB said the tower at LaGuardia had been busier than expected Sunday night because flight delays pushed the number of arrivals and departures after 10 p.m. to more than double what was scheduled, citing aviation analytics data from Cirium. The crash occurred with planes landing every few minutes, and at the same time the tower was coordinating an emergency response to an unusual odor reported on a separate late-night United Airlines flight, the NTSB said.
Investigators said the crash may also prompt questions about whether the FAA’s minimum requirement of two controllers on duty overnight is sufficient at major airports. The NTSB chair said the two-controller arrangement is typical for late-night shifts, and she said both controllers were early into their shift when the collision happened.
Homendy said LaGuardia has an advanced surface surveillance system intended to reduce runway incursions, and that controllers in those airports have tower displays meant to show the location of planes and vehicles. She said the system known as ASDE-X did not work as intended because the fire truck was not outfitted with a transponder, and because the close proximity of emergency vehicles merging kept the system from triggering an alarm.
Homendy said she believes more work is needed to determine whether an alert could have prevented the crash, and she said federal guidance has already moved toward equipping airport vehicles with transponders. She pointed to a May prior effort by the FAA encouraging the 35 airports with systems like ASDE-X to install transponders on vehicles and noting federal money was available to help pay for them.
The Port Authority of New York and New Jersey, which operates LaGuardia, said it was “unable to comment due to the ongoing investigation” when asked about the lack of a transponder on the fire truck. The NTSB said investigators have also not yet interviewed the firefighters, who were injured, or determined whether they braked or turned to avoid the collision.
The timeline that investigators said it compiled came after reviewing the Air Canada jet’s cockpit voice recorder. The NTSB said investigators recovered the recorder by cutting a hole in the aircraft’s roof, and it then identified the sequences involving the fire truck’s requests and the tower’s instructions in the final seconds before impact.
After the crash, investigators said travel operations resumed Monday at LaGuardia, but the runway where the collision happened remained closed. The NTSB said about one quarter of the airport’s flights were canceled Tuesday, citing FlightAware.com, and delays averaged more than four hours, though cancellations were not seen as spilling over to other airports.