This past Wednesday, there were two separate but related incidents of what “sleeping on the job” could have caused, when not one, but two commercial airplanes were unable to hail the traffic controller for landing clearance, yet landed safely with assistance from a regional control center.  This happened at Ronald Reagan Washington National Airport.  A United Airbus A320 was carrying sixty-three passengers and a crew of five, while an American Boeing 737 was flying with ninety-one passengers with a crew of six.  Thankfully, 165 persons were safe on the ground.  The lone controller, who had worked four consecutive overnight shifts,  had fallen asleep during the period of time the two pilots were calling in.   Concerns about worker fatigue have been voiced by The National Air Traffic Controllers Union and safety advocates for years.  

The FAA was asked four years ago to work with the controllers union to revise work schedules and practices and to develop a fatigue awareness program.  Their safety board stressed the “especially problematic” concerns regarding the common practice of scheduling controllers to work increasingly early shifts over a week.  Patrick Forrey, former president of the National Air Traffic Controllers Association said several towers in the U.S. have only one worker during the midnight shift.  It’s unknown just how common this practice is.  Transportation Secretary Ray LaHood noted that Reagan’s tower will get a second nighttime controller and he has asked the FAA to study staffing levels at other airports around the country.  Secretary LaHood stated, “One-person shifts are unsafe. Period.” 

Working at night has a greater impact than working the same number of hours in the daytime.  On average, shift workers lose 1 – 1 ½ hours of sleep for each 24-hour period.  This can build up a sleep debt of 6 hours after 4 nights.  Working more than three or four night shifts in a row can likely cause a significant sleep debt, bringing serious consequences for safety.  Our body clock is programmed to be awake during the day and asleep at night.  Night workers have to override their body clock to remain active at night. 

Prior to 2007, a study made by FAA Civil Aerospace Medical Institute showed there was widespread evidence of fatigue among air controllers.  Some of those findings were:

• More than 2/3 of those interviewed said they experienced attention lapses driving to work for early morning or midnight shifts;
• More than 1/3 reported falling asleep while driving to or from a midnight shift;
• 60 to 80 per cent had caught themselves about to doze off during early morning or midnight shifts. 

Fatigue has lead to many human errors. Mistakes made by shift workers in the early morning hours were critical factors in disasters at Three Mile Island, Chernobyl, Bhopal, and the Exxon Valdez oil spillage.  Fatigue-induced human errors bring major consequences for public safety, as well as for the workers involved.  It has been estimated that in the U.S., fatigue contributes to between 20 and 40 per cent of all commercial vehicle crashes, causing the loss of more than 15,000 lives.  Extreme fatigue may cause a person to “disengage” briefly into a “micro-sleep”.  When this happens at a critical time, an accident may result.  Micro-sleeps have been observed in train drivers and airline pilots during periods of critical operations, with the drivers and pilots sometimes being unaware that it was happening.  

There is no single method of shift management that fits all circumstances, but whichever method is used, should be tailored to the needs of the particular organization.  One thing is for sure, when it comes to airline safety, there should never be only one person in the control tower during late hours.  One person working alone with the responsibilities of that job should be able to take breaks, such as for meals and restroom. The pressures of such concentrated mental and visual work could be relieved by the presence of a co-worker.  Those that choose to fly night or day, as well as the airline crews, deserve to have their safety a top priority.

Source: Ft. Worth Star-Telegram, Bloomberg News; Department of Labour, New Zealand.govt.nz