An Airbus A320 was diverted from its course and landed in Syracuse, New York after the pilot of a US domestic commercial flight fell ill and died inside the cockpit.

"Medical emergency. Captain is incapacitated," the unidentified co-pilot of American Airlines Flight 550 told air traffic controllers in a calm voice, according to a recording posted on LiveATC.net.

Louise Anderson, who was among the 148 passengers, said she had dozed off on the flight. “What I woke up to was the flight attendant telling us we were making an emergency landing because the pilot was ill," she told the Associated Press.

Rumors were circulating of the pilot's death in the Syracuse airport, but they were only confirmed by an announcement on their subsequent flight to Boston, she added.

The US Federal Aviation Administration (FAA) says seven pilots for US airlines and one charter pilot have died during flights since 1994.

Passengers and crew 'not in danger'

James Record, a former airline pilot who now teaches aviation at Dowling College in Oakdale, New York told AP that there was likely minimal risk to the passengers and crew as the co-pilot was obviously qualified to fly the jet solo.

"He was doing what he's trained to do - fly the plane," Record said. "He was probably more concerned with the health of his buddy, his crew member," than his ability to fly, he said.

"We are incredibly saddened by this event, and we are focused on caring for our pilot's family and colleagues," American Airlines said in a statement.

Details of the medical emergency and the identity of the deceased pilot weren't immediately released. It also wasn't clear when the pilot died.

The 57-year-old pilot from the US state of Utah was pronounced dead on board the plane a few minutes after it landed, said Syracuse Police Lieutenant Eric Carr.

US regulations require that airline pilots pass a physical exam every 12 months and every six months if they are 40 or older.

jar/cmk (AP, Reuters)