U.S. aviation officials say a plane carrying first lady Michelle Obama had to abort a landing Monday after getting too close to a military cargo jet.

The Federal Aviation Administration announced Tuesday that a Boeing 737 carrying Mrs. Obama was within five kilometers of a massive C-17 cargo plane as it was preparing to land at Andrews Air Force base near Washington. Mrs. Obama’s pilot was told by air traffic controllers to delay its landing.

FAA standards require a minimum of eight kilometers between planes to avoid dangerous turbulence generated by a plane’s wake.

The aviation agency is investigating the incident has a possible error by traffic controllers at a regional radar facility near Washington.

The first lady was returning from New York, where she appeared on the daytime talk showThe View and at other events. Her plane landed safely.