TA-4F on river recky in Vietnam. The TA-4F is from a US Marine squadron nicknamed the "Playboys" that operated in South VietNam and were called "Fast FACS" which stands for fast forward air controllers. It was the job of these aircraft to detect enemy concentrations and then call in additional strike aircraft. They would then mark the target and control the attack. This was especially important if they were controlling an attack on enemy forces that were engaged with "friendlies" on the ground.