Other sleeping incidents
Of course the UK sleeping incident revealed Thursday isn't the first of its kind. Last February, the Dutch airline Transavia said it had launched an investigation after a Boeing 737 pilot was locked out of the cockpit and his first officer was later found asleep at the controls. The sleeping pilot had been left alone at the controls while his co-pilot took a bathroom break.
The incident took place in September 2012, when the airliner was flying from Greece to the Netherlands, a top Dutch safety investigation agency said. The 737 landed safely in Amsterdam as scheduled.
Fatigue played a role in the 2009 crash of Colgan Air Flight 3407 near Buffalo, New York, which killed 50 people. The National Transportation Safety Board report on the crash cited pilot error as a factor, adding, "the pilots' performance was likely impaired because of fatigue, but the extent of their impairment and the degree to which it contributed to the performance deficiencies that occurred during the flight cannot be conclusively determined."
Also in 2009, Northwest Flight 188 -- an Airbus A320 carrying 144 people and five crew members -- flew past the Minneapolis-St. Paul International Airport. One of the pilots told CNN that no one was sleeping on the flight deck at the time. The two pilots "became distracted by a conversation," according to a report by the National Transportation Safety Board.