A pilot on Delta Flight 143 from Detroit to Minneapolis on Sunday afternoon reported smoke in the cockpit during the flight, the Federal Aviation Administration confirmed to BringMeTheNews on Monday.
The FAA is investigating, spokeswoman Elizabeth Cory said. "We're still determining what happened," she said.
The MD-88 touched down without further incident at 4:48 p.m. at Minneapolis-St. Paul International Airport.
Pilots had notified airport officials that they had smelled fumes during the flight, airport spokesman Patrick Hogan told BringMeTheNews on Sunday. As a precaution, fire crews met the plane as it landed safely, he said.
Soot was found on one of the plane's engines after landing, and maintenance crews were investigating further, Hogan said.
The Delta plane had 148 passengers and six crew members, a Delta spokeswoman said.
She offered only this statement about the flight:
"While en route, the captain received an indicator warning (light) of a possible problem with one of his engines. The aircraft landed without incident. Maintenance is inspecting the aircraft."
The plane seemed to make an odd loop over Wisconsin before landing in Minneapolis about 23 minutes late, according to the live-flight tracking site FlightAware, but more information about that was not immediately available from Delta.