Two pilots on a packed Airbus passenger plane have admitted they were both asleep at the same time, leaving the aircraft flying on autopilot.
A shocking report has revealed one pilot awoke to discover both he and his colleague had been asleep in the cockpit of an 325-seat Airbus A330 plane operated by a British-based airline - which officials are refusing to name.
Highlighting the danger of fatigue on flights, the report to the UK's Civil Aviation Authority (CAA) showed that the pair nodded off after both having had only just five hours sleep in the previous two nights, the Sun reported.
Details of last month's mid-air scare come at a time when UK pilots' organisation Balpa is unhappy at proposed European changes to flight-time regulations.
The pilots' union said that it had repeatedly warned the CAA about the dangers of pilots feeling overly tired, and accused the regulator of being "complacent" about the problem.
Balpa said: "In the UK we have a strict set of flight safety rules which govern how long and how often a pilot can fly before their performance is impaired.
Warning against the European changes, the organisation warned they "would allow pilots to be flying aircraft whilst dangerously fatigued.
"These rules were not developed using scientific data and could have a grave impact on the safety of UK aviation."
Balpa said the EU proposals were "flawed in many areas", with pilots being legally allowed to land an aircraft having been awake for 22 hours, pilots operating longer-haul flights (such as west coast US) with only two crew rather than the current three, and pilots possibly being forced to work up to seven early starts in a row.
But the CAA said they think "overall it is a good package and not much different to what we have now."
Balpa said last month's incident "comes as no surprise", adding that it had "repeatedly warned the CAA of the risk of both pilots falling asleep, including in a letter to each member of the CAA board last year".
Balpa general secretary Jim McAuslan said: "British pilots want to make every flight a safe flight and tiredness is the biggest challenge they face.
"As the regulator responsible for UK flight safety, the CAA has been far too complacent about the levels of tiredness among British pilots and failing to acknowledge the scale of the under-reported problem.
"In fact, the CAA and Government are backing EU cuts to UK flight safety that will increase tiredness among pilots and the risk of dangerous incidents."
A CAA spokesman admitted the pilots falling asleep was "a serious incident" but insisted it was an isolated one.
"I think lessons will be learnt from this. We are circulating this report within the industry," they said.
"We don't know why the pilots had had so little sleep before this flight. They were taking it in turn to have rest periods, with the one always checking the autopilot and it looks as if both fell asleep at the same time."
"The new European rules will increase our oversight role of airline operators and place firm obligations on airlines to introduce comprehensive fatigue management policies and monitoring systems.
"This will maintain the UK's current high safety levels and will increase safety levels in some other EU states."Suggest a correction