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 Harrier cost and delay associated with such elaborate conversions was significant, and the concept was dropped. The Marines Corps' concept for deploying the Harriers in a land-based expeditionary role focused on aggressive speed. Harrier forward bases and light maintenance facilities were to be set up in under 24 hours on any prospective battle area. The forward bases, containing one to four aircraft, were to be located from the forward edge of battle (FEBA), while a more established permanent airbase would be located around from the FEBA. The close proximity of forward bases allowed for a far greater sortie rate and reduced