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.
Maurice Brennan assistant chief engineer working with Barnes Wallis on variable-geometry aircraft projects that would eventually become the basis of the AFVG project. However, he resigned again after ten months, joining Folland in 1960, replacing Teddy Petter as director and chief engineer. By this time Folland was part of Hawker Siddley, and he was responsible for developing the two-seat Gnat T.1, various twin engined and variable wing geometry Gnat proposals and the GERM hovercraft project (Ground Effect Research Machine). In 1961 he moved to Avro (also part of Hawker Siddley) succeeding Roy Ewans as a director and chief engineer. From 1961-1969 his