Chapter 1

Three factors appear to have brought the Air Force its larger role in the ARDF program. An Air Force briefing on the capability of the HAWK EYE, given to CINCPAC on 12 February 1966, let to his recommendation to the JCS that the USAF begin deploying 35 C-47 ARDF aircraft to RVN in April 1966. A consideration at Department of Defense level was that the Air Force already had the aircraft in its inventory to perform the mission; the Army did not. Finally, Gen. John P. Mc Connell, the Air Force Chief of Staff, gave full support to a "crash program" to meet the 35 C-47 aircraft requirement under the nickname PHYLLIS ANN. These aircraft (designates as RC-47s) were to be deployed to RVN between April and December 1966, after they had undergone IRAN and factory modification. At the same time, their crews were to be formed and then trained on basic C-47 equipment. A key Air Staff figure in generating this surge of activity was Maj. Gen. Robert N. Smith, Assistant DCS/Plans and Programs. After personally studying the Army ARDF operations in RVN, he realized the need for Air Force participation in ARDF as quickly as possible.

The PHYLLIS ANN aircraft were to have an important improvement in their ARDF capability beyond that of the HAWK EYE. This was side angle calibration, which made it possible to fix enemy transmitters in any direction without turning the aircraft. Without this feature, the crew would have to point the aircraft toward or away from the transmitter, as is the case with tha aural null technique. Therefore, side angle calibration reduced the possibility of compromise, and also enabled the crew to fix a radio transmitter in only short bursts.