Quotes of the Day

This really raises the stakes on the whole idea of "sleeping on the job."

On Wednesday night, an air traffic controller from Reno-Tahoe International Airport was suspended for being asleep and out of touch as an emergency medical flight was landing. With an ill patient on board and a fretting pilot, there was total radio silence as the plane circled the airport, waiting for instructions.

After the incident, which was the latest and most severe one in a string of controllers being asleep or unresponsive, the Federal Aviation Administration not only announced that it was putting a second controller on the late night shift in 27 towers, but also that the head of the FAA's Air Traffic Organization, Hank Krakowski, was resigning. FAA Administrator Randy Babbitt also issued a statement saying that there would be a "top to bottom review of the way we operate our air traffic control system." Secretary of Transportation Ray LaHood weighed in on NBC.

But amid all the breathless breaking news headlines, what's been missing from the conversation is some basic background info. A typical control tower has a few people on duty. Radar controllers spend their time turning pilots toward their final landing approach, while tower controllers lead planes to their gates. Supervisors make sure the process goes smoothly. In some of the recent incidents that have made the morning newspapers, one sleeping controller does not mean the entire control tower has gone dark, though many towers are indeed shorter-staffed during the overnight shift — when workers will no doubt be the most exhausted.

Furthermore, some airports have towers that go entirely unstaffed at some point during the day. When an airport lacks controllers, which is somewhat common, pilots are put on the same radio frequency as maintenance crew members on the ground.

This recent rash of sleeping controllers comes five years after a plane crash in Kentucky killed 49 people when a fatigued controller was working alone (though the responsibility was placed on the pilots.) Though there have been no major injuries from this year's incidents, they shed new light on air safety, and the fatigues that come with midnight shifts. Here's a timeline of this year's incidents of unresponsive air traffic controllers, which has led the FAA to take new action.

December 31, 2010: Errors by air-traffic controllers hit an all-time high in 2010, causing cockpit collision warnings dozens of times.

January 20: The National Transportation Safety Board investigated an incident in which an American Airlines jumbo jet, carrying 259 people, nearly missed colliding with two military cargo planes. One controller, who was responsible for collecting data, saw the flight paths and told a radar controller to stop the commercial plane's ascent at 20,000 feet. But the radar controller was distracted by other information from a Continental Airlines flight and did not hear the warning. The American Airlines plane continued to climb, not noticing any problems until its cockpit alarm went off. Reports vary, but the planes came as close as 2,000 yards from one another.

February 19: An air traffic controller reportedly slept for five hours while seven planes landed at McGhee Tyson Airport in Knoxville, Tennessee. According to the Washington Post, the radar controller had brought a blanket and made a bed out of couch cushions so he could take a nap. An anonymous federal official told the Post that another employee at the airport noticed the tower's silence, and repeatedly tried to wake up the controller. Each time she woke him, the controller promised he would get back to work. But as soon as she left, the controller dozed off again, while employees in other parts of the tower helped land the incoming planes. The FAA has said it is working to fire the controller, and the National Transportation Safety Board is evaluating the incident.

March 23: A tower supervisor fell asleep at Ronald Reagan Washington National Airport. The supervisor was on his fourth midnight shift in a row. Two pilots could not reach the tower by radio and had to land on their own, the Wall Street Journal reports.

March 29: Two controllers were unresponsive at Preston Smith International Airport in Lubbock, Texas. It took repeated attempts for a Fort Worth-based controller to hand off an inbound aircraft to the Lubbock airport, and the Lubbock tower failed to hand off a departing flight to Fort Worth. The FAA has suspended them.

April 11: A controller fell asleep at Seattle's Boeing Field/King County International Airport. He was monitoring local traffic while two other controllers monitored incoming and outgoing traffic. The controller was already facing disciplinary action for falling asleep on the job on two separate occasions during a January shift. The FAA has suspended him.

April 13: The aforementioned Reno air traffic controller was suspended after falling asleep on the job. The pilot of the emergency medical plane, making repeated urgent calls but getting no response. "We've got a pretty sick patient, we may just have to land," he said. After reaching the FAA in California, he was told to land at his own risk, which he did, safely.

• Megan Friedman and Megan Gibson