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 Siddeley P.1127 Kestrel with a much smaller counterpart on the fin to enable the nose to accommodate a tactical camera instead. An unusual feature of the P.1127 was the installation of a ram air turbine upon the rear fuselage just forward of the fin to provide power for ancillary services in the event of engine failure. Hawker Siddeley P.1127 The Hawker P.1127 and the Hawker Siddeley Kestrel FGA.1 are the experimental and development aircraft that led to the Hawker Siddeley Harrier, the first "vertical and/or short take-off and landing" (V/STOL) jet fighter-bomber. P.1127 development began in 1957, taking advantage of the Bristol