Two co-pilots safely landed a Continental Airlines jet en route from Belgium to Newark, N.J., after the captain died at the plane's controls.
Passengers on board the flight did not learn of the pilot's death until they landed and received cell phone calls from friends and family on the ground telling them what happened.
The pilot, Craig Lenell, 60, had worked for the company for 32 years and died of apparent natural causes. He had no known health problems.
Flight 61 safely was landed just after noon in Newark by two other trained pilots. By federal law, flights longer than eight hours are required to have three pilots on board. The flight time was scheduled for eight hours, 15 minutes.
Lenell died approximately three hours into the flight as the Boeing 777 cruised at 36,000 feet over the North Atlantic off the coast of Canada.
The co-pilots reportedly believed initially that the captain was just sleeping.
There were 247 passengers onboard.
Captain Was Dead When Doctor Arrived
Passengers on the flight said an announcement was made asking if a doctor was on board. The crew, however, did not alert the passengers to the pilot's death.
A Belgian doctor was called to the cockpit to treat Lenell, but said the pilot was "clinically dead" when he got to him.
There was "no chance at all" to resuscitate him, said Dr. Julian Struyven, a cardiologist from Brussels, who said he did not bother to use the plane's onboard defibrillator.
The pilot was removed from the cockpit and moved to a crew rest area immediately adjacent to the flight deck. A curtain was drawn across the area so that passengers could not see the body.
Two federal air marshals also were onboard the plane.
"The crew on this flight included an additional relief pilot who took the place of the deceased pilot. The flight continued safely with two pilots at the controls," Continental said in a statement.
The first officer on the flight had 11.5 years of service and approximately 9,800 flight hours, and the relief pilot had 22 years of service and approximately 15,500 flight hours, the airline said.
"The reason that we have two pilots in the cockpit is not only to have two brains and two sets of eyes focused on everything, but it's also for this contingency," said ABC News aviation analyst John Nance. "So if something happens physiologically to one of the pilots, the other one is seamlessly able to carry on."
Passengers said they did not learn of the captain's death until after the plane landed in New Jersey.
"Someone got a call on their cell phone, and we were wondering why there were so many calls, and [another passenger] just turned around and said to us [and said], 'Hey do you realize that our pilot died?'" said Lauren McDermott, a New Jersey native who lives in Holland and was on the flight with her husband and two young children. "So that's when we knew. And we knew that was the reason for the all the fire trucks when we landed as well."
McDermott said the crew gave no indication that the pilot was ill or had died.
"The crew remained very calm despite the fact that, you know, one of their colleagues had passed away," she said. "So I am very thankful to the crew for that, because I'm sure, you know, if passengers knew about it, it would probably cause more panic and anxiety on the flight. So I'm glad we only found out once we were safe."
Family Members Concerned for Continental Flight 61
Passengers exiting the plane did not seem shaken by the incident.
"I'm not going to stop flying. It was unfortunate," said Susan Morgan, a passenger from Houston who said automobile travel was more dangerous than flying.
Family members of passengers, who learned of the incident before the passengers themselves, waited eagerly at the terminal to pick up their loved ones.
Ted Reback of Short Hills, N.J., was driving to the airport to pick up his son Daniel, who was on the flight, when heard about the pilot's death on the radio.
"I know that they had multiple pilots on the plane, so there was no real concern," he said. "Then I found out when I got here that actually they had two additional crew, so they had three pilots."
Medical Requirements for Pilots
Midair deaths for pilots are exceptionally rare, experts told ABC News.com. Pilots undergo extensive tests to ensure they are physically and mentally fit before entering the cockpit.
Pilots, especially in the United States, face strict medical requirements to fly.
In 2007, Congress changed a federal law that rose the mandatory retirement age for pilots from 60 to 65 years old. Experts said the change was the first step in an effort to loosen some of the medical restrictions placed on pilots.
"The age 60 rule goes back to the 1950s and it really was arbitrary -- it wasn't based on any particular science," said Dr. Russell Rayman, executive director of the Aerospace Medical Association. "People are living longer, they're feeling better and we have better diagnostics than we did at that age."
Currently, all captains under 40 are required to take an annual physical. Heart problems, diabetes, psychosis and personality disorders all could ground a pilot.
After age 40, the FAA requires captains to pass two physicals a year.
"If you look at the history of commercial air in this country, there have been very, very few significant medical events in flight. We don't know of any that have caused an accident," said Rayman.
"The conclusion is that we have a pretty good medical surveillance," he said. "The only question is: Are we too strict?"
ABC News's Lauren Cox contributed to this report.