KC-135E StratotankerBoeing KC 135E airplane model. As part of a modification program, 161 Air Force Reserve and Air National Guard tankers were equipped with TF 33 PW 102 engines. The upgraded tanker, now known as the KC 135E, boasts a 14 percent improvement in fuel efficiency and a 20 percent increase in fuel offload capacity compared to the KC 135A. The current KC 135E model emerged from a 1982 initiative aimed at reducing noise, enhancing takeoff thrust, and lowering