Five myths about air traffic control

While air traffic controllers make the news anytime there's a near miss or airline disaster, most fliers rarely give them a second thought. Unless, of course, they want someone to blame for a delayed flight. Here are five myths about these unseen workers who do their best to make sure all goes smoothly in the nation's skies each day.

1. Air traffic control (ATC) comes down to a handful of overworked people watching the skies.

That may be Hollywood's version of what goes on, but the fact is that there are approximately 15,000 federal air traffic controllers on the job every day at 315 FAA air traffic facilities around the country, managing more than 87,000 daily flights across U.S. airspace. At a major airport, there could be 50-plus controllers on duty at a given time while at an air traffic control center, the number is in the hundreds.

Numbers aside, "their basic job is to make sure that aircraft are separated from each other," says Captain Chesley "Sully" Sullenberger, retired US Airways pilot, speaker, author and CBS News Safety & Aviation Expert. "They give pilots specific direction to maintain separation from each other, though pilots have a responsibility to see and avoid other aircraft when visibility allows."

In air traffic control towers at airports, controllers guide aircraft as they take off or land and taxi to or from the gate. Their primary function is to separate aircraft on the airport surface. For airports that don't have towers, controllers at remote approach control facilities are in charge of guiding aircraft in and out.

Controllers in en route facilities guide airplanes flying at high altitudes through large sections of airspace. As aircraft fly across the country, pilots talk to controllers in successive en route facilities. There are 21 en route centers that control aircraft flying through U.S. airspace and work closely together to ensure a smooth transition of all aircraft though the entire region.

"Each controller is working a sector," says Sullenberger. "It's a slice of airspace and it's their responsibility."

In some places, like the Northeast, where Sully says that the intertwining number of flight paths is best visualized as "a spaghetti bowl," the issues faced by air traffic controllers are more complex, which is why there are many more delays. That's especially true when weather requires pilots to deviate their course.

"There's not a lot of excess room," says Sully, "which is why they may need to shut off arrivals or departures. They have to strategically avoid sending aircraft into areas impacted by weather. It's a little like opening and closing a valve."

2. Air traffic controllers can talk aircraft down to a safe landing.

"That's actually happened on a few occasions," says Sully. "It's usually with smaller, general aviation aircraft, flown by pilots in a difficult weather situation who have trained for visual flight but who find themselves in restricted visibility."

Exceptions aside, Sully says that "a safe landing is collaboration between pilots and air traffic control, and each one has a part to play in the interaction. It's an aerial ballet that we do. But the pilot is the final authority and responsible for the safety and control of the aircraft."

3. Near-misses happen all the time, due to stressed and overtired ATC personnel.

"They do happen" says Sully, "but it's fairly rare."

There are fixed required horizontal and vertical separation distances and heights that air traffic controllers must maintain between aircraft need to observe at various stages of their flight. The vast majority of the time, ATC makes sure that aircraft keep those distances. Yet Sully acknowledges that the "potential for risk can be great. It's a people, technology and system design issue. There's a need to address each of those areas. They're interconnected and there are layer upon layer of checks and balances in place so that everyone has the same awareness."

Captain John Cox, a retired airline captain with US Airways and author of the Ask the Captain column on this site, says that "technically, a near miss occurs anytime that there is a loss of separation. Aircraft are miles apart at the same altitude in flight and about 1,000 feet when it's visual. We're not talking 100 or 200 feet."

Cox also points out that every aircraft has a traffic collision avoidance system (TCAS) and that those systems monitor the airspace around an aircraft for other aircraft equipped with a corresponding TCAS. This is independent of ATC and it's designed to warn pilots and prevent midair collisions.

There's also newer ATC technology, called NextGen, which uses both radar and satellite-based technology, " an "attempt to move the FAA out of 1950's methodology of aircraft separation. It's about 30% to 40% complete," Cox says.

4. Air traffic controllers are glued to a screen and never see the aircraft they're working with.

It's true that air traffic controllers monitor radar screens to track aircraft. As aircraft fly over radar sites, the data from those radars is communicated digitally via telecommunications lines to controllers hundreds or even thousands of miles away.

But Sully says that many people imagine that an ATC center is like something out of CSI, showing highly advanced graphic displays in real time. The reality is that the technology in use today is older and is not yet as good as depicted in movies and television.

"Life is harder than that," says Sully. "Much of the art is done visually, especially at control towers at major airports."

It's a two-prong system: Radar controllers may be watching blips on a screen, but tower controllers, if the weather is good, are watching the actual aircraft.

Air traffic controllers, says Sully rely on good training and judgment and "good human performance. Automation will not do everything for us."

5. As long as aircraft are safely landing and taking off, air traffic controllers have done their job.

At larger airports, ATC is responsible for all movements and for making sure that not only aircraft but airport vehicles are doing what they are assigned to do on specific routes.

"Much of the risk of collision occurs on the ground, not in the air" says Sully. "It may be an aircraft or an airport vehicle that is not where they're supposed to be. They may be too close to an active runaway. ATC has to deconflict these movements."

Otherwise, it can lead to what the FAA terms "Runway Incursions," which they define as "involving the incorrect presence of an aircraft, vehicle or person on the protected area of a surface designated for the landing and take-off of aircraft."

An "Operational Incident" is a type of Runway Incursion where there is "less than required minimum separation between 2 or more aircraft, or between an aircraft and obstacles, (vehicles, equipment, personnel on runways) or clearing an aircraft to take off or land on a closed runway."

From October 2013 to October 2014, there were 257 such incidents at US airports, versus 243 in the previous year.

It's yet another aspect of the high stakes three dimensional chess game that air traffic controllers play every day.