Hawker Siddeley Harrier the AV-8C configuration; this programme involved the installation of ECM equipment and adding a new inertial navigation system to the aircraft's avionics. Substantial changes were the Lift Improvement Devices, to increase VTOL performance; at the same time several airframe components were restored or replaced to extend the life of the aircraft. Spain's Harriers, designated AV-8S or VA.1 Matador for the single-seater and TAV-8S or VAE.1 for the two-seater, were almost identical to USMC Harriers differing only in the radios fitted. The Royal Navy's Fleet Air Arm (FAA) operated a substantially modified variant of the Harrier, the British Aerospace Sea Harrier.
Hawker Heron prototype was ordered for evaluation. The first flight of the prototype, serial number "J6989", flown by P.S.W. Bulman was made in 1925. Despite being heavier than the similar powered Woodcock, it was 15 mph (24 km/h) faster and was praised by the pilots that flew it for its excellent handling properties. Due to little interest from the Air Ministry, only one aircraft was built and it was returned to Hawker after testing. Hawker Heron The Hawker Heron was the first fighter aircraft designed at Hawker Aircraft with a basically metal structure. Sydney Camm was the chief designer that introduced what