by KING5.com

Posted on April 14, 2010 at 6:46 PM

Updated today at 8:25 AM


SIOUX FALLS, S.D. – A United Airlines Boeing 757 from Washington D.C. to Seattle made an emergency landing in Sioux Falls, SD after the pilots smelled smoke in the cockpit.

United Airlines says it was smoke that forced the emergency landing, but passengers say it smelled like someting else.

“I noticed this really heavy pungent smell and to me I thought… it smells like burning oil, like hydraulic fluid or something,” said Roger Tilton, a passenger on the flight.

No one described any panic on the plane, but passengers were relieved to be safely on the ground.

The Sioux Falls fire department responded with 11 firefighters and stood by as mutual aid to the Air National Guard, but their services were not needed.

The first officer said they did have heavy black smoke in the cockpit and put on their oxygen masks. They got the plane down as fast as they could at the closest airport that could handle the 757.

The plane landed safely in Sioux Falls and the passengers on board were expected to be flown to Seattle later this evening.

It’s is still not clear what caused the smell, but cabin air issues are in the news more and more. Just Tuesday an American Airlines flight from Paris to Dallas had to divert to Iceland because of fumes.