Robertson began his military career in 1980 by enlisting as a security policeman with the 182nd Tactical Air Support Group
. He later became a pilot and served in many roles, including forward air controller, air liaison officer and aircraft commander.
(4.) History of the 23d Tactical Air Support Squadron, 1 July-30 Sept 1971, in History of the 504th Tactical Air Support Group
, vol 3, pp.
Perhaps one of the reasons that such incidents were comparatively few is the use of the Tactical Air Support Groups
-- the demothballed AT-6 (Harvard) trainers which carried army officers as observers.