The Central Intelligence Agency and Overhead Reconnaissance; the U-2 and Oxcart Programs, 1954-1974

The danger posed by the growing number of SA-2 sites in the PRC was clearly demonstrated on 1 November 1963, when a second Project TACKLE U-2 was lost near the Kiangsi-Chekiang border on its way back from photographing the PRC's Shuangchengzi missile test range. As was the case after the first operational loss over China in September 1961, President Kennedy ordered a standdown of overflights of mainland China. This standdown lasted almost five months.

As a result of this second loss over the PRC, the Office of Special Activities began installing a new 30-channel telemetry system aboard Detachment H U-2s to monitor various aircraft functions. Known as BIRDWATCHER, this unit periodically broadcast a burst of data to the airbase that launched the U-2. This data burst contained a status report on all the major systems aboard the plane, such as airspeed, altitude, exhaust temperature, fuel supply, film supply, and oxygen supply. BIRDWATCHER provided project managers with a benchmark of aircraft performance that could be used to determine if a lost plane had been shot down at altitude or had suffered mechanical failure. $ ^{54} $

BIRDWATCHER's first operational use came on 16 March 1964, when overflights resumed with a mission over southern China. The PRC was now a high-priority target for the U-2 because more data were needed to prepare National Intelligence Estimates due in the autumn. Of particular concern was the PRC's nuclear program. Despite the high priority of its missions, Detachment H's resources remained scarce. It was short of both pilots and planes and never had more than three U-2s or six qualified Nationalist Chinese pilots at any one time. By the spring of 1964, crashes during training and the two losses over the mainland had reduced Detachment H to only two qualified pilots, one of whom suffered from ulcers and a nervous disorder. Indeed, this pilot had every reason to be nervous; he flew three of the next four Detachment H overflights and became the third Nationalist Chinese pilot to be shot down over the mainland.

This loss came on 7 July 1964. The Nationalist Chinese pilot's last transmission was that his System-XII unit had alerted him that he was being tracked by the FAN SONG radar. BIRDWATCHER data revealed that the aircraft was at penetration altitude and all systems