“After our aircraft experienced a mechanical problem shortly after takeoff, it remained airborne to burn fuel and then landed safely,” United said in a statement. “Passengers disembarked at the gate and another flight is scheduled to depart tomorrow.”
An initial maintenance inspection suggests a problem with a hydraulic pump on the plane, which had 256 passengers on board, United Airlines said.
Sparks flew off the plane as it climbed after takeoff, according to a video posted online that claims to show the flight.
The Federal Aviation Administration is investigating what happened to Flight 149, which left Newark Airport late Wednesday night, and then declared an emergency. The Boeing 777-200 plane had been en route to Sao Paulo, Brazil, before returning to Newark, the FAA said.
The hydraulic system on the Boeing 777 runs key systems, such as the landing gear, flaps and brakes. There are three redundant hydraulic systems on the aircraft, meaning that two can fail and the aircraft can still operate normally.
The plane circled over the Atlantic Ocean to burn fuel before returning to the airport about two hours after takeoff, flight tracking data shows.
CNN has reached out to the Port Authority of New York and New Jersey for comment.