An American Airlines plane headed from Phoenix to Boston made an emergency landing in Syracuse this morning after the pilot died mid-flight.

According to a spokeswoman, Flight 550 left Phoenix at 11:55 p.m. but was diverted before it reached its destination, touching down around 7 a.m. EDT. The first officer safely landed the Airbus A320 with 147 passengers and five crew members onboard.

“We are incredibly saddened by this event, and we are focused on caring for our pilot’s family and colleagues,” the airline statement said. It's unclear when the pilot died, nor what caused his death.

According to the NY Post, the first officer calmly called the airport tower and said, “American 550. Medical emergency. Captain is incapacitated” before requesting to land.

Passengers only discovered the pilot was dead after they had already boarded another flight to Boston.