The Pratt & Whitney JT8D is a turbofan family that powered several major generations of short- and medium-haul jet airliners. Revenue service began on the Boeing 727 in February 1964. The engine subsequently appeared on the Douglas DC-9, Boeing 737-100 and -200, and the later McDonnell Douglas MD-80 family.[1]
Service development
Pratt & Whitney's programme chronology dates DC-9 revenue service to December 1965 and 737 revenue service to February 1968. These installations made the JT8D common to aircraft with different layouts: the three-engine 727, the rear-engined DC-9 and the underwing-engined 737. The shared engine family consequently served airframes with quite different installation requirements.[1]
The JT8D-200 entered revenue service in October 1980. It extended the family's use into the MD-80 generation and later supported a Boeing 727 re-engining programme. Pratt & Whitney records FAA approval of the JT8D-200-powered 727 modification in September 1996, illustrating how a later engine standard could also be applied to an existing airframe.[1]
Original and later models
The manufacturer's overview distinguishes the earlier JT8D models, broadly in the 14,000–17,000 lbf class, from the JT8D-200 series at approximately 18,500–21,700 lbf. These are family ranges rather than universal ratings. A specification for an individual engine must identify its complete model designation and the conditions under which its thrust is measured.[2]
Applications and designation
Pratt & Whitney lists variants including the JT8D-7, -9, -15 and -17 in the earlier series, and the -209, -217 and -219 in the later group. Its applications also include later Caravelle versions, the Dassault Mercure and Kawasaki C-1. The breadth of this list demonstrates that the engine's history extends beyond the three best-known American airliner families.[2]
Environmental development
Later development included an emissions-reduction combustion package known as the E-Kit. Pratt & Whitney describes it as reducing nitrogen-oxide emissions from the JT8D-200. This was a modification to combustion performance within an established engine family, separate from changes to aircraft noise certification or the replacement of the complete powerplant. It forms part of a longer history of adapting the engine to changing operating requirements.[2]