 Northrop Grumman selected the -219 to re-engine the US Air Force's fleet of 19 E-8 Joint STARS aircraft, which would allow the J-STARS more time on station due to the engine's greater fuel efficiency.NATO also planned to re-engine their fleet of E-3 Sentry AWACS aircraft.The -219 is publicized as being half the cost of the competing powerplant, the CFM International CFM56, and is 40 dB quieter than the original JT3D engines.