Designed and built as the RAF's first dedicated four-engine long-range maritime patrol aircraft, the Avro Shackleton was the final expression of Avro's classic heavy bombers, the Lancaster and Lincoln. Retaining the wing and landing gear of the Lincoln, the Shackleton had a larger, rounder and shorter fuselage, which provided space for a crew of 10. Armament included two 20mm cannon in the nose, two in a dorsal turret, and two machine guns in the tail plus bombs or depth charges, depending on the mission.
Entering service in 1951, the plane underwent two primary modifications over the years. The MR.2 gained a semi-retractable 'dustbin' radome, allowing a 360-degree scan as well as changes allowing the plane to fly with three engines feathered. The Shackleton MR.3 added greater overall capabilities with improved ailerons, wing tip tanks and better crew quarters. By the late 1960's the Shackleton was being replaced by the Nimrod jet patrol aircraft. However, this grand dame was not finished yet.
Responding to the loss of Airborne Early Warning (AEW) capability with the demise of the Royal Navy's carriers, twelve Shackletons were pressed into service as AEW.2 aircraft in 1971. The radome was replaced by a 'guppy' radar unit forward of the weapons bay, and many internal changes were made to accommodate the electronic gear and radar operators. From 1974 to 1991, the Shackleton AEW.2 flew missions over the North Sea, Arctic Ocean and western Atlantic until relieved by the Boeing E-3D Sentry.
A single Shackleton (WL790) is operated in the USA and, until recently, a second one flew in South Africa as a part of the SAAF "Historic Flight." Another Shackleton, "WR963" (the sister ship to WL790), is based at Coventry Airfield in the UK, and is undergoing a refurbishment program which should make it airworthy again in the next few years. For now, WR963 makes weekly engine runs and is available for tours.