The JT9D family of engines consists of three distinct series. The JT9D-7 engine covers the 46,300- to 50,000-pound-thrust range, and the JT9D-7Q series has a 53,000 pound thrust rating. Later models, the JT9D-7R4 series, cover the 48,000-to 56,000-pound-thrust range.
These three engine types power 747, 767, A300, A310 and DC-10 aircraft. For JT9D-7R4 installed in A300-600, A310 and 767, the engines are approved for 180-minute ETOPS operation.