 New turbofan engines would give these E-3s longer ranges, longer time-on-station, and a shorter critical runway length.If the modification is carried out, the E-3s could take off with full fuel loads using runways only long, and also at higher ambient temperatures and lower barometric pressures, such as from bases in mountainous areas.The E-8 Joint STARS briefly fitted a test aircraft with the new Pratt & Whitney JT8D-219 turbofans, stated as having one-half the cost of the competing engine, the CFM56, the Air Force is again studying the possibility of replacing the E-3's original turbofan engines with more-efficient ones.