With the delivery of the 59th and final KC-10A Extender in late March, the US Air Force (USAF) has completed a six-year upgrade programme for the aerial refuelling fleet. The modifications involved replacing the aircraft's Flight Management System (FMS) 800 with the new Communication, Navigation, Surveillance/Air Traffic Management (CNS/ATM) system. The CNS/ATM replaces the gyroscopes of FMS 800 with an infrared laser system which increases fuel efficiency for the aircraft.