Possible smoke in cockpit forces emergency landing in NJ: Officials

A United Airlines plane heading for Seattle had to return to Newark Airport Sunday morning because of possible smoke in the cockpit and cabin, officials said.

United Flight 409 landed after the flight crew noticed an "unusual smell," according to the airline and the Federal Aviation Administration. FAA spokeswoman Kathleen Bergen said an initial investigation found a possible problem with the air conditioning system.

On Saturday night, a Berlin-bound flight had to return to Newark after there was a "mechanical issue with an engine," according to a United spokesman. The Federal Aviation Administration said the left engine overheated.

No injuries were reported in either incident.