A new study unveiled by Federal Aviation Administration officials has stated that the air traffic controllers' work schedule leaves them highly fatigued making them less alert hence, endangering the safety of the national air traffic system.

This study has been kept under wraps by the government. Agency officials have refused to publish its copy despite the fact that repeated requests have been made for the same over the past three months. The Associated Press was able to have a draft of the report on December 1, 2011. FAA posted the report online in December 2012.

Main aim for carrying out the study was a suggestion by the National Transportation Safety Board to the FAA and the National Air Traffic Controllers Association that controller schedules should be changed. They should be given more rest, so they can have enough sleep.

The study has found that nearly two in 10 controllers had committed errors in the previous year like bringing plane too close together and more than half of the incidents were blamed on fatigue.

In fact, a third of controllers have blamed fatigue as high or extreme safety risk. More than 6 in 10 have said that they have fallen asleep while driving to or from midnight shifts, which generally starts at 10pm and end around 6am.

During a work week, controllers are able to have 5.8 hours of sleep per day. A survey of 3,268 controllers was carried out in which work schedules and sleep habits. A field study was also carried out in which sleep and mental alertness of over 200 controllers at 30 air traffic facilities was assessed.

"Even with 8 to 10 hours of recovery sleep, alertness may not recover to the full rested baseline level, but may be reset at a lower level of function", read the report. The 270-page report has made 17 recommendations to the FAA.