WASHINGTON (AP) - NASA researchers warned the Federal Aviation Administration nearly four years ago that air traffic controllers' schedules lead to chronic fatigue and undermine safety.
The FAA has kept the NASA study secret.
Voluntary reports from a confidential aviation safety database run by NASA show that controllers are still complaining they make dangerous errors because their work schedules don't provide enough time for sleep. Schedules cited by the study as especially fatiguing are a week of five midnight shifts - usually from 10 p.m.-6 a.m. - and six-day work weeks for several weeks in a row, usually with at least one midnight shift per week.
A controller at Louisville International Airport in Kentucky described bringing two cargo planes dangerously close together as they descended during a midnight shift last October. He had cleared one plane to descend from 8,000 feet to 6,000 feet, only to find another plane that he had thought was farther behind had nearly caught up. The second plane was at an altitude of 7,000 feet, while the first plane was still descending.
Explaining what led to the error, the controller said he regularly works five midnight shifts a week. "On the weekends I sleep normally at night," he said. "Monday nights are usually accomplished by staying up for 24 hours." He recommended controllers be allowed to work four 10-hour midnight shifts a week rather than five 8-hour shifts to allow more time for recovery. NASA researchers made the same recommendation in 2011.
Two controllers working at Albany International Airport in New York last summer described clearing a small airliner for takeoff on a runway that was closed for maintenance. The first controller acknowledged he forgot to tell the second controller, who cleared the takeoff, that the runway was closed. Both controllers cited fatigue as the reason for their mistakes.
"For months, we have been working six-day work weeks with two hours of OT (overtime) regularly scheduled on the front or back of our shifts," explained the first controller.
"We here have been working six-day work weeks with minimal staffing, minimal breaks," said the second controller.
They also said rest breaks during shifts weren't frequent enough because staffing levels are too low.