First lady Michelle Obama's plane had to abort its landing at Joint Base Andrews after it came closer to another military jet than it should have, officials said.
Air traffic controllers apparently allowed the planes to get too close to each other. The required separation is five miles apart, but controllers allowed the first lady's Boeing 737 to get 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, rough air that can dangerously disrupt planes behind them. A government official told ABC News that the military plane had not cleared the runway as Michelle Obama's plane approached.
Air traffic controllers at the approach control facility in the Washington, D.C. area were handling Obama's plane, dubbed Executive One Foxtrot. They told the plane's pilot to do a standard go-around and circle for an additional time to create the appropriate distance, which they did.
Even after the cargo plane landed, though, the controllers were reportedly still worried that they wouldn't be able to clear the runaway in time for Obama's jet and asked the pilots to loop around the airport one more time. A source says nobody aboard the plane was aware of anything out of the ordinary.
There was no panic caused by the incident and no emergency vehicles were called in. Sources tell ABC News no one on the plane, including the first lady, were aware of the delay or the high-sky maneuvers.
"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 C17," 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 Jill Biden and attended other events Monday.
The incident comes at a time when air traffic controllers are already under scrutiny.
There have been at least five reported incidents of air traffic controllers falling asleep on the job in the last two months, which has prompted negotiations between the government and the controllers' union to change the way controllers are scheduled to work.
The FAA has acknowledged there is a widespread problem with fatigue among controllers and that the agency is taking steps to improve the situation, including an additional hour of rest and changing their schedules so they cannot work a three-day weekend.
Transportation Secretary Ray LaHood told ABC News today he is "hopping mad" about these recent incidents and that the agency "will just not tolerate it from our controllers."
"Guiding planes full of people in and out of airports is serious business. And so my reaction is I'm hopping mad about it and we will continue to suspend controllers and doing investigations until we put a stop to this," he said. "My idea is zero tolerance for this kind of behavior -- zero."
Feb. 19: A controller in Knoxville, Tenn., went to sleep on the job during a midnight shift. Sources told ABC News that the controller made a bed on the floor of the control tower with couch pillows.
March 23: A controller on his fourth consecutive overnight shift at Washington, D.C.'s Reagan National Airport left the radio tower silent after apparently falling asleep. Two commercial airliners were forced to land on their own.
March 29: Two controllers at Preston Smith International Airport in Lubbock, Texas, did not hand off control of a departing aircraft to another control center and it took repeated attempts for them to be reached.
April 11: A controller at Boeing Field/King County International Airport in Seattle fell asleep on the job. Boeing Field does not handle any commercial air travel.
April 13: A controller at the Reno-Tahoe International Airport in Nevada was sleeping as a plane carrying a crticially ill patient was trying to land.
April 16: An air traffic controller fell asleep on the job at an air route control center in Florida.
April 17: An air traffic controller near Cleveland was suspened after being caught watching a movie -- Samuel L. Jackson's "Cleaner" -- on the job.
ABC News' Huma Khan and Sunlen Miller contributed to this report.