Multiple recent disclosures of US air traffic controllers sleeping while on duty has forced the US FAA to change controller scheduling practices to allow more time between shifts.

The incidents began with a widely-reported event at Washington National airport in which flights tried to contact a sleeping controller for roughly 15 minutes while trying to land at the facility. FAA is investigating two other incidents of unresponsive controllers that emerged as it was reviewing staffing levels and controller behaviour after the National incident.

On 13 April a controller reportedly fell asleep at Reno-Tahoe International airport while a medical flight carrying an ill patient was attempting to land.

The latest sleeping controller episode occurred on 16 April. FAA suspended a controller in Miami for reportedly falling asleep during the midnight shift. At the time 12 controllers and two managers were on duty.

Following the Miami incident FAA issued new scheduling rules for controllers, requiring a minimum of nine hours between shifts, up from current minimums of eight hours. Controllers are now prohibited from swapping shifts unless they have had a minimum of nine hours off between the last shift worked and the one they'd like to staff.

Additionally, controllers are no longer allowed to switch to an unscheduled midnight shift following a day off, and FAA managers are required to schedule their own shifts to ensure greater coverage in the early morning and late night hours.

The fallout from the high profile events triggered the resignation of the head of FAA's air traffic control organisation (ATO) Hank Krakowski on 14 April.

Other actions FAA unveiled include an independent review of the air traffic control training curriculum and qualifications to ensure controllers are properly prepared.

Source: Air Transport Intelligence news