A passenger with no flying experience landed a plane in Florida after the pilot passed out.
In a audio recording from the flight, the passenger, Darren Harrison, can be heard telling air traffic control a "serious situation" was unfolding.
An air traffic controller - who also teaches new pilots - helped guide the man down to Palm Beach International Airport just after noon on Tuesday.
The two later met on the tarmac for a hug.
The pilot of the Cessna 208 had been flying to Florida from the Bahamas when he told his two passengers he wasn't feeling well, according to the Federal Aviation Administration (FAA).
He fell against the controls, putting the small aircraft into a nosedive and a sharp turn.
The nature of the medical emergency has not been revealed, but the pilot is being treated in hospital.
An on-board conversation between Mr Harrison and air traffic control caught the drama:
HARRISON: "I've got a serious situation here. My pilot has gone incoherent. I have no idea how to fly the aeroplane."
CONTROL: "ATC: 333 Lima Delta, Roger, what's your position?"
HARRISON: "I have no idea. I can see the coast of Florida in front of me but I have no idea."
CONTROL: "Maintain wings level and just try to follow the coast, either northbound or southbound. We're trying to locate you."
Robert Morgan, an air traffic controller at Palm Beach International Airport, was on his break when a colleague came to alert him to the situation.
A long-time flight instructor with more than 20 years' experience in air traffic control, Mr Morgan had never flown the specific model - a single-engine Cessna 208 - but was able to use a map of the aircraft's cockpit to give instructions to the flier.
"I knew the plane was flying like any other plane. I just knew I had to keep him calm, point him to the runway and tell him how to reduce the power so he could descend to land," Mr Morgan told WPBF-TV.
He told the FAA the surreal experience was "like a movie".
In the recording, Mr Morgan is heard teaching the man to "push forward on the controls and descend at a very slow rate" as he approaches for landing.
After the plane landed, Mr Morgan can be heard in the recording praising the heroic passenger to other pilots on the tarmac.
"Did you say the passengers landed the airplane?" the pilot responded. "Oh, my God. Great job."
The passengers had planned to land at Boca Raton in Florida, but Mr Morgan instead guided Mr Harrison to Palm Beach airport because it had a longer runway, was less congested, and had much-needed radio coverage, the FAA said.
Under Mr Morgan's tutelage, Mr Harrison flew the plane into its final approach, successfully landing the aircraft at 16:37 local time. Neither passenger had any injuries.
The FAA is investigating.