Air traffic controllers at Westchester Airport in the US have been caught on video sleeping, reading and using mobile phones when they should be on duty.

Fox 5 News received footage from an unidentified informant who was concerned about the threat to public safety. The video shows controllers doing everything but scanning the skies for incoming or departing aircraft.

The airport is a destination for seven different commercial airlines. Seven days a week from 6am to 11pm, air traffic controllers guide flights serving nearly two million passengers a year and up to 100 planes take off and land every hour.

The source told Fox 5 News: "I'm upset and extremely concerned with things taking place at Westchester tower.

"It poses an extreme threat to public safety. If someone's not paying attention, 100 per cent attention, between separating arriving and departing air traffic, you could have a near miss or worse."

The video and photographs given to the news channel appear to show up to ten air traffic controllers sleeping, reading, using laptops or mobile phones.

Although the Federal Aviation Administration (FAA) wouldn't agree to an on-air interview with Fox 5 News, they did release a statement which said: "The use of cell phones is strictly prohibited in the tower, however, employees have temporarily been permitted to use devices for texting and e-mail only on their personal breaks, but not while on position directing air traffic."

They also explained that the lift is out of service at Westchester tower and, as the break room is eight flights downstairs, the controllers union and the FAA can to an agreement to make the back portion of the tower room a temporary break room.

However, Fox 5's source says that controllers have been sleeping and using distracting devices int he tower for many years.

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