Michelle Obama's plane 'too close' to cargo jet
A plane carrying First Lady Michelle Obama had to abort a landing near Washington DC after an apparent air traffic controller's error.
The aircraft carrying her came within three miles of a military cargo jet, rather than the minimum five-mile distance set by US aviation officials.
The Federal Aviation Administration (FAA) said the planes "were never in any danger". Both landed safely.
The FAA is investigating Monday's alert as a possible controller's error.
It was the latest in a series of episodes involving apparent lapses by air traffic controllers.
Several controllers and supervisors have been suspended by the FAA since late March over incidents involving workers sleeping on the job, almost all of them during overnight shifts.
Another controller was suspended on Monday for watching a film when he was supposed to be monitoring aircraft in Ohio, the FAA said.
On Tuesday, air traffic controllers at Andrews Air Force Base in Maryland ordered the Boeing 737 carrying Mrs Obama to abort its planned landing after it came within three miles of a C-17 cargo plane.
Under FAA rules, a minimum separation of five miles was required between the C-17 and the next plane to avoid dangerous turbulence from the cargo jet's wake.
The Boeing 737 was instructed to perform a "go around" and subsequently landed safely, the FAA said in a statement, without naming Mrs Obama as a passenger.
The FAA is investigating the incident as a possible mistake by controllers at a regional radar facility in Warrenton, Virginia.
The presidential aircraft Air Force One and other government planes are based at Andrews. The air space around the military base is administered by the civilian FAA.