Having entered service with the RAF in 1991, the Sentry AEW fleet has now officially been retired. (Janes/Patrick Allen)
The United Kingdom has retired the Boeing E-3D Sentry AEW1 after 30 years of operational service.
A decommissioning ceremony was held at the type's main operating base at Royal Air Force (RAF) Waddington in Lincolnshire on 28 September.
The RAF received the first of an eventual seven Sentry aircraft in 1991, taking over the UK's airborne early warning and control (AEW&C) role from the piston-engined Avro Shackleton, and in place of the aborted British Aerospace Nimrod AEW1.
Based on a modified Boeing 707/320 commercial airframe, the Sentry is built around a 9.1 m diameter elliptically cross-sectioned rotating radome that sits atop the fuselage. This radar has a range of more than 400 km (which equates to a coverage area of more than 500,000 km
of airspace) to look down and detect, identify, and track low-flying aircraft over land or water. It achieves this by eliminating ground/water clutter returns that confuse other radar systems. Crew members perform surveillance, identification, weapons control, battle management, and communications functions.
Though a small fleet, the Sentries were deployed in support of every UK air operation from the first Gulf War through to missions against the Islamic State. With just seven airframes to begin with, the Sentry capability had been whittled down in recent years as planned capability upgrades were shelved as cost saving measures. By the time of the retirement ceremony, just three aircraft remained in a flyable condition. The type's last operational mission was flown by 8 Squadron on 5 August.