Falling asleep on the clock is pretty much a no-no anywhere. But as the air traffic controller who took a 24-minute nap late Tuesday night on 22nd May 2011 last year learnt it the hard way that napping on some jobs makes national news.
As bad as it was for the guy inside the tower at Reagan National Airport to take a snooze, he was just one of many air traffic controllers inbound airliners would have talked with as they approached the airport near Washington D.C. And as was demonstrated, there are several options pilots can pursue if no one’s answering inside the tower. In fact, many airports do not have anybody working the overnight shift in the tower and aircraft come and go all night. Granted, these aren’t usually busy commercial airline hubs.
Major airlines operate on instrument flight plans and are (normally) in contact with an air traffic controller the entire time the airplane is moving. A simplified overview of a typical flight involves talking to many people, all of whom often are referred to as “air traffic controllers.”
At Reagan National on Tuesday night, the pilots of two aircraft were unable to establish contact with the control tower. But the pilots were in contact with air traffic controllers who followed them until their arrival at Reagan. One of them advised the first aircraft, an American Airlines flight from Dallas-Fort Worth, to follow the procedures for arriving at an uncontrolled airport.
Procedures for landing at an uncontrolled airport are familiar to pilots and commonly used by many airlines at airports across the country. Pilots simply announce their location on the airport frequency designated for such use, then complete the landing following standard patterns while remaining vigilant of other aircraft. In addition to the American flight from Dallas, a United Airlines flight from Chicago also landed using the uncontrolled airport procedures.
Once the American flight was on the ground, the pilots successfully roused the controller, who subsequently admitted to falling asleep, according to a preliminary report by the National Transportation Safety Board..
A typical airline flight will be handled by roughly four distinct groups of air traffic controllers: Ground, tower, approach/departure and center. Within some of these, the planes might be handled by several people in the same facility.
Air traffic controllers inside the tower at Boeing Field in Seattle.
After confirming a flight plan and receiving IFR (instrument flight rules) clearance, the pilot typically will contact a ground controller at the airport. That controller will shepherd the plane from the gate to a position near the runway. From there, the control tower takes over and informs the pilots when they are clear to take off. Once the plane is airborne, the tower typically hands it off to departure control, or simply “departure.”
Departure control controllers work at the terminal radar approach control, or TRACON, facility that handles departures and arrivals for that airport. TRACON facilities usually are very close to the airport they serve, but may be many miles away from smaller airports under their control. Air traffic controllers at these facilities sit in darkened rooms, monitoring aircraft on radar screens that display flight information, altitude and speed alongside an icon indicating the plane’s location.
The view for an air traffic controller at the Seattle TRACON. SeaTac airport is located near the center of the picture.
Once an aircraft is handed off to departure, it is considered “under positive control,” meaning it is being followed on a radar screen at all times. Departure control handles the aircraft for a limited amount of time within 50 miles or so of the airport before handing pilots over to an air route traffic control center, known simply as “center.”
There are 20 center facilities in the contiguous 48 states and one each for Alaska and Hawaii. Each is known simply by the cities where they are located. A pilot flying from Seattle to Chicago would be handed off from Seattle Center (first picture) to Salt Lake Center to Minneapolis Center and finally to Chicago Center. These controllers also sit in darkened rooms and monitor a wide area, often handing off aircraft to another controller within the same room as an aircraft passes through a particular center’s airspace.
A map showing the 20 “center” facilities in the contiguous United States.
Once an aircraft nears its destination, the center controller passes it off to a TRACON facility, where it is guided in by an approach controller such as “Chicago approach.” The approach controller typically handles an aircraft from inside the same 20 to 50 mile radius until it can navigate using an approach procedure for the destination airport.
When the pilot is established on the specific approach (usually when they are more or less lined up with the runway, though they could still be several miles away), the aircraft is handed over to the control tower. The control tower guides it in using radar and visual contact. Once the airplane is off the runway, the tower hands it to ground control for the taxi to the gate.
The air traffic controller caught snoozing was working in the control tower. It isn’t unusual for one person to handle tower and ground control duties for the relatively small number of aircraft coming and going overnight.