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.
British Aerospace Sea Harrier and were inducted the same year. Ten more Sea Harriers were purchased in November 1985; eventually a total of 30 Harriers were procured, 25 for operational use and the remainder as dual-seat trainer aircraft. Until the 1990s, significant portions of pilot training was carried out in Britain due to limited aircraft availability. The introduction of the Sea Harrier allowed for the retirement of India's previous carrier fighter aircraft, the Hawker Sea Hawk, as well as for the Navy's aircraft carrier, INS "Vikrant" (ex-HMS "Hercules"), to be extensively modernised between 1987 and 1989. India has operated Sea Harriers from both the