1966 April
6994th Security Squadron Headquarters established at Tan Son Nhut, Vietnam, under the Project name, “Combat Cougar”.
1966 June
First operational mission for EC-47 out of Tan Son Nhut. Project “Drill Press” began in Hue Phu Bai, Vietnam.
1966 July
Detachment 1 of the 6994th Security Squadron established in Nha Trang, Vietnam.
1966 September
Detachment 2 of the 6994th Security Squadron established in Pleiku, Vietnam.
1967 March
Tide 86, flying out of Nha Trang, was shot down. Losses include:
TSgt. Raymond F. Leftwich (6994th)
A1C Charles D. Land (6994th)
A1C Daniel C. Reese (6994th)
Major Leroy P. Bohner (361st)
Major Ivel D. Freeman (361st)
Captain Roger P. Richardson (361st)
SSgt. Prentice F. Benton (361st)
1967 September
Ground Attack in Nha Trang. TSGT Frederick T. Sebers lost.
1968 February
Project “Drill Press” moved from Hue Phu Bai to Pleiku.
1969 February
CAP 72 flying out of Pleiku is shot down. Losses include:
TSgt. Louis J. Clever (6994th)
SSgt. James V. Dorsey (6994th)
TSgt. Hugh L. Sherburn (6994th)
SSgt. Rodney H. Gott (6994th)
Sgt. Clarence L, McNeill (6994th)
Lt. Col. Harry T. Niggle (362nd)
Maj. JHomer M. Lynn (362nd)
Maj. Robert E. Olson (362nd)
Capt. Walter F. Burke (362nd)
MSgt. Wilton N. Hatton (362nd)
1969 April
Detachment 3 of the 6994th Security Squadron established in Nakon Phanom Royal Thai Air Force Base, Thailand.
1969 September
Detachment 1 moved from Nha Trang to Phu Cat, Vietnam.
1969 October
Prong 33 flying out of Phu Cat crashes due to mechanical problems. Losses include:
SSgt Elmore L. Hall (6994th)
Sgt Michael L. Stiglich (6994th)
1st Lt. Ronald H. Knight (361st)
1st Lt. Max E. Rosen (361st)
Capt. Bradley R. Ransom (361st)
TSgt Sylvester W. Redman (361st)
1970 April
CAP 53 flying out of Pleiku is shot down. Losses include:
SSgt Michael R. Conner (6994th)
1st Lt. George M. Wall (361st)
Survivors include:
Sgt Phil Ehrhorn (6994th)
Sgt Danny E. Russell (6994th)
Sgt Ron Lawler (6994th)
1st Lt. “Nasty” Nasipak (361st)
Capt. Carl Lemon (361st)
SSgt. Edward J. Mosley (361st)
1970 June
“Combat Cougar” renamed to “Combat Cross” due to suspected compromise of nickname.
Detachment 2 moved from Pleiku to Da Nang, Vietnam.
1971 October
Detachment 1 (Phu Cat) is deactivated.
1972 November
Baron 56, returning to base in Nakhon Phanom RTAFB, Thailand, crashes due to mechanical problems. Losses include:
MSgt. John W. Ryon (6994th)
Capt. Robert A. Kohn (361st)
Survivors include:
SSgt Paul W. Weyandt (6994th)
Sgt Thomas E. Way (6994th)
Sgt Charles F. Fidroeff (6994th)
Sgt Laurent A. Morin (6994th)
Sgt Claude W. Pennell Jr. (6994th)
2nd Lt. Edgar H. Hirshouer III (361st)
1st Lt. Michael G. Danielle (361st)
Lt. Col. Howe L. Vandegriff (361st)
1972 December
6994th Headquarters moved from Tan Son Nhut to Nakon Phanom, Thailand.
Detachment 3 moved from Nakon Phanom RTAFB, Thailand to Ubon, Thailand.
1973 February
Baron 52, flying out of Ubon, is shot down. Losses include:
SSgt Todd M. Melton (6994th)
Sgt Joseph A. Matejov (6994th)
Sgt. Peter R. Cressman (6994th)
Sgt Dale Brandenburg (6994th)
Capt George R. Spitz (361st)
2nd Lt Severo J. Primm III (361st)
Capt Arthur R. Bollinger (361st)
1st Lt. Robert E. Bernhardt (361st)
Detachment 2 (Da Nang) is deactivated.
1974 January
6994th Headquarters moved from Nakon Phanom, Thailand, to Ubon, Thailand.
1974 February
Detachment 3 (Ubon) is deactivated.
1974 June
Last EC-47 mission flown.
6994th Security Squadron is deactivated.