Royal Air Force and replacement by the F-35, the RAF Lossiemouth-based 15 (Reserve) Squadron (the Tornado Operational Conversion Unit) was disbanded in March 2017. Lightning: On 23 November 2015 it was announced that a total of 138 F-35Bs will be ordered. 617 (The Dambusters) Squadron officially reformed on 18 April 2018 as an RAF Lightning Squadron. The first four aircraft arrived at RAF Marham on 7 June 2018. The Sentry AEW1, based at RAF Waddington, provides airborne early warning to detect incoming enemy aircraft and to co-ordinate the aerial battlefield. The Sentinel R1 (formally known as ASTOR – Airborne STand-Off Radar) provides a
RAF Mount Pleasant the barracks, messes and recreational and welfare areas of the station, and was nicknamed the "Death Star Corridor" by personnel. Mount Pleasant was opened by Prince Andrew on 12 May 1985, becoming fully operational the following year. The station was constructed as part of British efforts to strengthen the defence of the Falkland Islands following the 1982 war with Argentine forces. It remains the newest purpose-built RAF station and replaced previous RAF facilities at Port Stanley Airport. RAF Mount Pleasant is the newest permanent airfield in the Royal Air Force. The RAF previously had a small airfield at Stanley airfield