An investigation is underway today to determine what precipitated air traffic controllers' allowing first lady Michelle Obama's plane to come too close to a military cargo plane, forcing it to abort its landing and rekindling some anxiety among the flying public.
The plane, carrying Obama and the vice president's wife, Jill Biden, eventually landed safely at Joint Base Andrews Monday, officials said. The incident is one of several recent mishaps involving air traffic controllers, including those in which controllers have been caught falling asleep and watching movies on the job.
But Aviation expert and ABC News consultant John Nance said there's no need to fear flying. "The basic problem is it's a human system ... we expect perfect performance by humans a 100 percent of the time, Nance said.
"Whenever you build a system to expect that kind of performance, you're going to be disappointed over and over again. We've got great people in air traffic control but we really have historically expected too much of them."
Michelle Obama and Jill Biden were returning from making several appearances in New York Monday when air traffic controllers apparently allowed the planes to get too close to each other. The required separation is five miles but controllers allowed the Boeing 737 that was carrying the two women to come within three miles of the giant C-17 military cargo plane, Federal Aviation Administration sources told ABC News.
The distance is important because large planes generate wake turbulence, the equivalent of two miniature tornadoes streaming off the plane. The rough air dangerously disrupts the plane behind it.
"If this hadn't been an aircraft as big as a 737, it could have been very significant because those horizontal tornadoes … can upset a smaller airplane," Nance said. "A 737 would have a bit of a problem but nothing really terribly lethal. The problem is you don't want this kind of operational error anywhere anytime and they unfortunately do occur."
Air traffic controllers handling Obama's plane, dubbed Executive One Foxtrot, ordered the pilot to do standard S-turns to create the appropriate distance, which they did.
"Can we slow down for executive one foxtrot," the air traffic controller said in audio obtained by liveatc.net.
Even after the military cargo plane landed, though, the controllers were reportedly still worried that the C-17 wouldn't clear the runway in time for Obama's jet to land. The air traffic controller ordered the first Lldy's pilot to abort the landing and circle the airport.
There was no panic caused by the incident and no emergency vehicles were called in. No one on the plane, including the first lady, was aware of the delay or the high-sky maneuvers, sources said.
"FAA controllers at Andrews Air Force Base instructed an incoming Boeing 737 on approach to Runway 19 to perform a 'go around' on Monday, April 18, 2011 just after 5 p.m. because the plane did not have the required amount of separation behind a military C-17," the FAA said in a statement. "The FAA is investigating the incident. The Boeing 737 landed safely after executing the go around. The aircraft were never in any danger."
The first lady was returning to Washington, D.C., from New York, where she appeared on "The View" with Biden and attended other events Monday.
The incident comes at a time when air traffic controllers are already under scrutiny.