The Federal Aviation Administration says United Flight 409 bound for Seattle returned to the airport at about 9:15 a.m. Sunday after reports of possible smoke in the cabin and cockpit.
A United spokesman says the flight crew noticed an unusual smell in the cockpit. No injuries were reported.
The emergency was the second in as many days. On Saturday night, a United flight to Germany had to return to the airport after experiencing engine problems.
On Sunday, the FAA said one of the engines on the Berlin-bound flight apparently overheated on takeoff. An agency spokeswoman says that contrary to published reports, the aircraft didn’t blow a tire during takeoff.