Donald Trump's plane was diverted to Nashville International Airport Wednesday after reporting engine problems, officials said.
The pilot declared an emergency but didn't ask for assistance, a source told CBS News.
The Trump Boeing B757 landed at about 4 p.m., reports CBS Nashville affiliate WTVF-TV.
The Federal Aviation Administration says it will investigate.
Trump, a Republican presidential contender, was on his way to Little Rock, Arkansas for a rally when the starboard engine experienced a mechanical issue 50 miles outside Nashville, WTVF says.
A source told the station one of the engines was sticking in neutral.
Trump was on the plane, and boarded another one shortly after landing, WTVF says.
Trump's plane remained at the airport to be checked out, the station adds.
The plane is a Boeing 757-200 built in 1991 with Rolls-Royce RB.211 Series engines.