New York’s LaGuardia airport is facing significant delays and cancellations for the second straight day following the deadly collision Sunday night between an Air Canada Express jet and a fire truck on the runway.

The Federal Aviation Administration said it does not expect one of the two runways at the New York airport to reopen until Friday.

FlightAware, a flight tracking site, said 221 flights, or 20%, had been canceled and 214 delayed as of 9:45 a.m. EDT. The FAA warned of major delays throughout the day.

National Transportation Safety Board chair Jennifer Homendy said she plans to hold a press conference later in the day on the investigation and detail some findings from the cockpit and flight data recorders that were recovered from the CRJ-900 jet operated by regional partner Jazz Aviation.

The NTSB plans to interview an air traffic controller who was juggling another emergency in the run-up to the crash.

The accident while landing, which killed both pilots and seriously injured another nine people, has revived concerns over limited air traffic control staffing at major U.S. airports.

Homendy said the collision shortly before midnight on Sunday happened during an overnight shift for the controller.

U.S. air safety experts said communications between the plane that was landing, the controller and the trucks would be key areas of the investigation.

Air crashes typically are caused by multiple factors. According to separate audio posted by liveatc.net, an unidentified controller who appears to be the one involved in the crash, told another pilot after the collision that he had been dealing with an emergency earlier.

“I messed up,” he said in a shaken voice.

Air traffic controllers routinely handle multiple flights, and four commercial pilots told Reuters it was not uncommon to have one controller covering both the ground and tower, two distinct air traffic control roles, at LaGuardia and other major metropolitan airports.

—

(Reporting by David Shepardson; Editing by Chizu Nomiyama and Franklin Paul)