The Australian Maritime Safety Authority (AMSA) said Tuesday it received an emergency beacon activation at 8:15 a.m. local time, coming from approximately 270 nautical miles (500 kilometres) east of Sydney.
The AMSA requested Air Canada Flight AC033, a Boeing 777 en route from Vancouver to Sydney with 270 passengers and 18 crew aboard, to divert to the area of the beacon.
"The location of the beacon was within a flight path, so we needed to assess the situation and the Boeing 777 was the closest asset available to us," Jo Meehan of the AMSA told the Australian Broadcasting Corp.
Capt. Andrew Robertson, of Vancouver, who was piloting the Air Canada flight, says he was contacted by Australian air traffic control and asked to help.
"There's a ship, a yacht in distress, may have sunk, and you are the closest aircraft. Would you be able to assist," was the message Robertson said he received.
He asked for the location of the boat so that he and his crew could determine if they had the fuel to search for the boat in distress.
"Once we'd put that into our computer ... we actually determined that we had the fuel," Robertson said.
He noted that the aircraft's flight management system doesn't take into account dropping in altitude and then climbing back up, but Robertson said the crew believed they had enough fuel.
The Air Canada flight crew was using binoculars provided by passengers to look for the yacht as Robertson took the plane down to about 5,000 feet.
"I made a PA announcement to ask the passengers [to watch for the boat] because it's like looking for a needle in a haystack," he said.
"Almost right away, my first officer spotted something," Robertson said, adding that at 5,000 feet is was hard to make out any details.
"So I went from 5,000 down to 3,700 feet ... and they saw what they thought initially were three people on the deck, but it turns out there was only one," he said.
Robertson said the 777 is a big plane to be down at that level doing search and rescue.
"The passengers were awesome," Robertson said, adding he heard no complaints about the detour.
Air Canada spokesman Peter Fitzpatrick said everybody on board was "really happy and excited by the outcome," even though it delayed the flight by roughly 90 minutes.
With the boat's location confirmed, a police vessel was dispatched to the demasted yacht, which was running low on fuel and drifting further out to sea.
Robertson said he understood the sailor aboard the yacht was rescued a few hours later.
"It was very exciting," he said.
Canadian singer Jill Barber, who was on the Air Canada flight, tweeted: "It was not what I'd call an uneventful @AirCanada flight to Australia. Very impressed with the response of captain, crew and passengers!"
Yacht was low on fuel
An Air New Zealand A320 en route to Sydney from Auckland was also asked to divert to the area, confirm the yacht's position and get more details on the situation.
"It is believed the solo yachtsman left Pittwater, Sydney, two weeks ago heading for Eden in New South Wales, but had been drifting away from land since last week," Australian authorities said.
Pittwater is a part of Sydney's Northern Beaches region.
A merchant vessel, the ANL Benalla, arrived alongside the yacht later in the afternoon to provide shelter from strong winds until a police vessel from Sydney could reach the sailor Tuesday evening.
An AMSA spokeswoman said it was unusual for commercial aircraft to be called in to assist in a search and rescue effort.
"It's not common, but that's not because we try to avoid doing it," she told the Australian Associated Press. "It's because the nature of the incidents that we have aren't necessarily so remote that we can only rely on the commercial airlines."