An off-duty pilot stepped in to help fly a Boeing 737 after the first officer fell ill mid-flight

• An off-duty pilot stepped in to help fly a Boeing 737 after the first office was taken ill.
• The off-duty pilot was a passenger on a Westjet flight from Calgary to Vancouver.
• Pilots are trained for emergencies, and flights always have multiple pilots for safety.

An off-duty pilot stepped in and helped to fly and land a Boeing 737 when the flight's first officer was suddenly incapacitated mid-flight.

The transportation website Paddle Your Own Kanoo first reported that the incident took place on a WestJet flight from Calgary to Vancouver on the morning of December 4.

The off-duty pilot was known to the crew and could be called upon to assist in flying the Boeing 737. The pilot then sat in the cabin for the rest of the flight.

"During cruise, the first officer reported feeling ill and was unable to continue their duties. One of the passengers on board was a Westjet pilot who was able to assume the first officer's duties," a preliminary report from the Canadian Transportation Safety Board said, per the Aviation Herald.

"The incapacitated first officer sat in the cabin for the remainder of the flight. The flight crew did not declare an emergency or request a priority handling. The aircraft landed without further incident," the report added.

WestJet did not immediately respond to a request for comment from Business Insider on the incident.

If a pilot is taken ill, airlines normally declare an emergency and land the plane as soon as possible.

Retired US pilots Kent Davis and Mark Stephens previously told Business Insider that it is "not a big deal" when pilots become unwell during a flight because they are trained to handle these situations.

Stephens said there are at least two pilots on domestic flights, while international flights can have two pilots and two captains.

"Pilots know what they are doing, and they do it repeatedly," he said.

Sometimes, pilots become more seriously ill. In July, an Airbus A320 from London Luton to Lisbon, which was carrying almost 200 passengers, was met by paramedics on landing after the copilot fainted in midair.

"The captain landed the flight routinely in line with procedures and passengers disembarked normally," an airline spokesperson told BI at the time. "At no point was the safety of the flight compromised."

In October, it was reported that a Turkish Airlines captain died in midair on a flight from Seattle to Istanbul, and the plane was diverted for an emergency landing in New York.

"After the initial medical intervention on board proved ineffective, the cockpit crew, consisting of one captain and one co-pilot, decided to make an emergency landing," an airline spokesperson said at the time.

One pilot named Ken Allen told BI he suffered an aneurysm while flying a small plane with a friend and one passenger. He fell unconscious, and the passenger managed to safely land the plane instead.

Stephens, one of the retired US pilots, told BI that there are procedures in place for life-threatening situations. Flight attendants are trained in CPR and have defibrillators, and many planes have a direct line to medical staff.