What is Pratt & Whitney JT9D?
The JT9D engine family 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 -7R4 series, cover the 48,000- to 56,000-pound-thrust range. For JT9D-7R4 twinjet installations, the engines are approved for 180-minute ETOPS (Extended-range Twin-engine Operations). [[Category:Aircraft engines]]