An American Airlines Group Inc. captain died after falling ill during a Phoenix-to-Boston flight, forcing the first officer to divert the plane to Syracuse, New York.

A nurse on board attempted to revive the pilot, who suffered from an unknown illness, American spokesman Ross Feinstein said Monday. Flight 550 left Phoenix at 11:55 p.m. Sunday carrying with 147 passengers and five crew members.

The first officer took control of the Airbus Group SE A320 jet and touched down safely at Syracuse Hancock International Airport at 7:13 a.m. Monday, Feinstein said. It was unclear whether the captain died in the air or after landing, said Feinstein, who wouldn't release the pilot's name or age. The passengers arrived in Boston later Monday after American dispatched a new crew to Syracuse, Feinstein said.

A pilot's death in flight is a rare occurrence, but not unprecedented. Cockpit automation has helped ensure safety in case of the loss of one of the two crew members on the flight deck, ensuring that jetliners can be flown by a single pilot in an emergency.