The year 2016 marks the 50th anniversary of the widespread introduction of Airborne Radio Direction Finding in the Vietnam War. The Army’s 3d Radio Research Unit had been at it on a limited basis since 1962, but the decision in 1965 to introduce American ground troops in large numbers brought a corresponding demand for increased SIGINT support. The Air Force’s HAWKEYE program had proved that the venerable C-47 “Gooney Bird” could be utilized as an effective ARDF platform, and in early 1966 the green light was given to project PHYLLIS ANN, initially calling for 35 C-47 airframes to be modified. Two other Gooney Birds were deployed to the war zone as collection-only COMINT platforms under project DRILL PRESS.
By mid-year, an ARDF command and control structure was in place that, in its basic form, would function until U.S. withdrawal seven years later. MACV was very much a ground-oriented command, and that was reflected in the supporting SIGINT organization. At the top of the heap was ASA’s 509th Radio Research Group, which oversaw the ground-based Direct Support Units and the 224th Aviation Battalion (Radio Research) and its ARDF aircraft. To fly and maintain the PHYLLIS ANN “Electric Goons”, the USAF established three reconnaissance squadrons, later redesignated Tactical Electronic Warfare Squadrons. To operate the ARDF and other SIGINT equipment in the “back end” of these aircraft, USAFSS activated the 6994th Security Squadron at Tan Son Nhut, along with detachments at Nha Trang and Pleiku.
Below are listed some 1966 events which set the stage for ARDF operations in general and for the TEWS and the 6994th Security Squadron in particular. For a more extensive interactive timeline of the war, click on this link to the Department of Defense Vietnam War Commemoration.
10 DRILL PRESS flies very succssful orientation mission NW of Saigon.
11 Southeast Asia Operational Requirement (SEAOR) 32 issued, outlining requirement for USAF ARDF aircraft.
02 460th Tactical Reconnaissance Wing activated at Tan Son Nhut.
10 Project PHYLLIS ANN is officially launched, calling for modification of 35 C-47 airframes for ARDF.
28 Seventh Air Force activated at Tan Son Nhut, replacing the 2d Air Division as the top USAF command in Vietnam.
06 "McConnell-Johnson Agreement" (USAF-Army) spells out roles and missions, including ARDF, for aircraft of both services.
08 The 360th (Tan Son Nhut) and 361st (Nha Trang) Reconnaissance Squadrons are activated.
11 HAWKEYE crew makes 11 fixes near Tay Ninh.
12 Gen. William Westmoreland, COMUSMACV, lauds DRILL PRESS contributions.
15 6994th Security Squadron activated at Tan Son Nhut.
14 First PHYLLIS ANN aircraft, serial number 43-15112, arrives at Tan Son Nhut without ARDF equipment installed. (Other sources list 26 May.)
01 509th Radio Research Group activated at Tan Son Nhut, replacing the 3d RRU as the top ASA command in Vietnam.
01 224th Aviation Battalion (Radio Research) activated, controlling 4 ARDF Aviation Companies (RR), also est. this date.
06 6994th flies first mission, fixing a record 19 targets aboard a PHYLLIS ANN aircraft.
01 ARDF Coordination Center established, matching SIGINT consumer requests with ARDF assets through MACV Intelligence (J2).
01 Detachment 1, 6994th Security Squadron, activated at Nha Trang.
09 HAWKEYE prototype (45-0925) flies its last mission before redeploying to CONUS to be fitted with production ARDF gear.
20 Det. 1, 361st Recon Sqn, activated at Pleiku. (Later became 362s Recon/TEWS.)
24 DRILL PRESS deploys to Da Nang in support of USMC's Operation HASTINGS.
23 Entire DRILL PRESS contingent deployes to Pleiku. Situation unsatisfactory, leaves 3 days later.
01 Det. 2 of 6994th activated at Pleiku.
02 DRILL PRESS tasked with "national level" mission to monitor Cambodian air traffic control of French President Charles DeGaulle's flight.
24 DRILL PRESS plus 4 PHYLLIS ANN ARDF aircraft deploy to Da Nang (until 7 December) for special mission support.
16 Already TDY, DRILL PRESS moves from Da Nang to Phu Bai (see 24 Sept.)
17 First PHYLLIS ANN aircraft (44-77016) arrives Nha Trang.
10 PHYLLIS ANN aircraft begin dropping psychological warfare leaflets to disguise the ARDF mission.
08 First PHYLLIS ANN aircraft (44-77254) arrives Pleiku.
12 First PHYLLIS ANN ARDF mission flown from Pleiku.
31 Only 25 of 47 programmed PHYLLIS ANN aircraft have arrived in country.