United Kingdom The Royal Air Force purchased seven E-3Ds by October 1987, designated Sentry AEW.1 in British service.[1][79] As of December 2020, only three remained in service after one was withdrawn from service in 2009 to be used as spares, two were withdrawn in March 2019 and a further one withdrawn in January 2020.[80][81] The fleet had been given an out of service date (OSD) of December 2022.[82] They form the E-3D Component of the NATO Airborne Early Warning and Control Force.[83] However, that date was accelerated pursuant to the 2021 defence review and the aircraft made its final flight in U.K. service in August 2021.[84]