The Lockheed L-1011 TriStar, commonly referred to as the L-1011 (pronounced "L-ten-eleven") or TriStar, is a medium-to-long-range, wide-body trijet airliner. It was the third widebody airliner to enter commercial operations, after the Boeing 747 and the McDonnell Douglas DC-10. The aircraft has a seating capacity of up to 400 passengers and a range of over . Its trijet configuration places one Rolls-Royce RB211 engine under each wing, with a third, center-mounted RB211 engine with an S-duct air inlet embedded in the tail and the upper fuselage. The aircraft has an autoland capability, an automated descent control system, and available lower deck galley and lounge facilities.