Big eyes and Batcats

摘要

As early as 1966, North Vietnam possessed the expertise to detect an F-105D Thunderchief flying at 15,000ft above the northeast corner of Thailand, track it over Laos and follow its course over North Vietnam. The jet was only lost to controllers when the pilot descended below 3,000ft to take advantage of terrain masking. This increased threat to American aircraft added to the already dangerous environment the US Air Force, Marine Corps and Navy found themselves in - during April 1965 two F-105s were shot down by North Vietnamese MiGs after a Soviet-style ground-controlled intercept (GCI) system had been used to guide the fighters to the inbound strike aircraft. Although the US had radar ships in the Gulf of Tonkin, and a ground site at Nakhon Phanom Royal Thai Air Force (RTAF) base, there were major gaps in coverage. An airborne early detection and warning system to locate and track any threats to US strike aircraft was vital.