Chilling audio has been released of the moment the captain of a United Airlines Boeing 787 jet yelled 'mayday' after he lost an engine soon after takeoff.

'Failure, engine failure, left engine, United 108. Declaring an emergency. Mayday- Mayday-Mayday,' one of the pilots of United Flight 108 said calmly to air traffic control after taking off on Friday July 25.

The flight from from Washington Dulles Airport bound for Munich, Germany had only just cleared 5,000 feet of altitude with its tanks full of fuel for the eight-hour flight over the Atlantic, when its left engine suddenly lost power.

In audio posted online, what followed was 30 minutes of aerial tension as the pilots were forced to hold in order to dump fuel before landing back at the airport they'd just departed.

'United 108 Heavy, roger that, sir. Are you able to make your way back into the field at this time? You can turn right heading 100, if able,' an air traffic controller responded, attempting to guide the aircraft back toward the airport.

'Right turn,' the pilot answered as alarms could be heard sounding in the cockpit of the aircraft and fuel levels were assessed.

'When able just say intentions, sir. There's nobody between you and the field. I'm gonna keep you on the downwind at 6,000,' the controller advised, referring to the safe altitude for the holding pattern.

With more than eight hours of fuel still onboard and only one functioning engine, the pilots advised they would 'have to take a few laps in holding' circling northwest of the airport to dump excess fuel.

A transatlantic United Airlines flight was forced to make an emergency landing just minutes after takeoff when its Boeing 787-8 Dreamliner suffered a mid-air engine failure

The engine failure occurred only moments after takeoff from Washington Dulles Airport

For the next 20 minutes, the massive twin-engine Dreamliner circled the skies above Northern Virginia, held aloft by only its right engine.

The aircraft had 219 passengers and 11 crew members onboard

FlightRadar24 tracking data showed the aircraft making a loop at 6,000 feet as the crew prepared to return to Dulles.

Air traffic controllers cleared all other planes from the area as Flight 108 lined up for its final approach.

After a smooth touchdown, with only one engine operational the aircraft was not able taxi under its own power and had to be towed to a gate, where all passengers and crew deplaned safely.

United Airlines confirmed the incident in a statement referring to it as a 'mechanical issue,' and confirmed the flight's subsequent cancellation.

Footage from FlightRadar24 shows the plane circling above Washington Dulles airport to dumpe fuel

The Dreamliner remained grounded at Dulles for three days where United maintenance crews worked on repairing the malfunctioning engine. The plane has since been returned to service

The airline arranged alternate travel for all passengers, but declined to provide further details about the engine failure.

The Metropolitan Washington Airports Authority confirmed the emergency landing and said the aircraft was inspected at the gate

The Dreamliner remained grounded at Dulles for three days where United maintenance crews worked on repairing the malfunctioning engine.

The plane has since been returned to service without issue.