being re-delivered from August 1979. The upgrade included extensive modernisation of the aircraft's electronic suite. Changes included the replacement of the 1950s ASV Mk 21 radar used by the Shackleton and Nimrod MR1 with the new EMI Searchwater radar, a new acoustic processor (GEC-Marconi AQS-901) capable of handling more modern sonobuoys, a new mission data recorder (Hanbush) and a new Electronic Support Measures (Yellow Gate) which included new pods on the wingtips. Provision for in-flight refuelling was introduced during the Falklands War (as the MR2P), as well as hardpoints to allow the Nimrod to carry the AIM-9 Sidewinder missile to counter enemy Argentine Air Force maritime surveillance aircraft. In preparation for operations in the Gulf War theatre, several MR2s were fitted with new communications and ECM equipment to deal with anticipated threats; at the time these modified aircraft were given the designation MR2P(GM) (Gulf Mod). The Nimrod MR2 carried out three main roles: Anti-Submarine Warfare (ASW), Anti-Surface Unit Warfare (ASUW) and Search and Rescue (SAR). Its extended range enabled the crew to monitor maritime areas far to the north of Iceland and up to out into the Western Atlantic. With Air-to-Air Refuelling (AAR), range and endurance was greatly extended. The crew consisted of two pilots and one flight engineer, two navigators (one tactical navigator and a routine navigator), one Air Electronics Officer (AEO), the sonobuoy sensor team of two Weapon System Operators (WSOp ACO) and four Weapon System Operators (WSOp EW) to manage passive and active electronic warfare systems. Until 1992, the Nimrod MR2 was based at RAF Kinloss in Scotland (120, 201 and 206 Squadrons), and RAF St Mawgan in Cornwall (42 and 38(R) Squadrons). Following Options for Change, 42 Squadron was disbanded and its number reassigned to 38(R) Squadron. The Nimrod MR2 aircraft was withdrawn on 31 March 2010, a year earlier than planned, for financial reasons. The last official flight of a Nimrod MR2 took place on 26 May 2010, with XV229 flying from RAF Kinloss to Kent International Airport to be used as an evacuation training airframe at the nearby MOD Defence Fire Training and Development Centre. AEW3 In the mid-1970s a modified Nimrod was proposed for the Airborne Early Warning (AEW) mission – again as a replacement for the Lancaster-derived, piston-engined Shackleton AEW.2. Eleven existing Nimrod airframes were to be converted by British Aerospace to house the GEC Marconi radars in a bulbous nose and