The 1st Marines battalion commander explained how the system operated in late spring 1952:
I was in an outpost watching an air strike. I asked Captain Shoden [John C., the battalion forward air controller] to work out some idea of flak suppression. Shoden, G-2, and others worked two or three weeks to complete the first plot of antiaircraft positions. My idea was to have a plane start a run and then pull up before finishing the dive. The enemy antiaircraft gunners could not tell that the pilot was pulling out at an extremely high level. The batteries would fire and Marine observers would plot their positions from their fires. Then, the Marine artillery would lay a heavy barrage on these positions.[108]
[108] LtCol Gerald T. Armitage interv by HistBr, G-3 Div, HQMC, dtd 15 Aug 61.
While observing an air strike from the Marine division sector, General Lamson-Scribner noted that prior to the strike there had been no preparatory firing on enemy antiaircraft artillery positions. After the strike he discussed this matter with General Selden, who “directed me to discuss with his chief of staff what I had observed and my suggestions that division firepower for ‘flak suppression’ be coordinated with air strikes.”[109] The upshot of this was that the division chief of staff suggested that the 11th Marines regimental commander and his staff members develop an SOP[110] for using artillery flak suppression fires in support of close air support strikes. It was believed that proper utilization of these fires would reduce aircraft losses and further increase the opportunity for a successful close air support mission by destruction of enemy antiaircraft weapons.[111]
[109] MajGen Frank H. Lamson-Scribner ltr to Hd, HistBr, G-3 Div, HQMC, dtd 12 Oct 66.
[110] An SOP, standing operating procedure, is a set of instructions for conducting operations that lend themselves to established procedures. JCS, JD, p. 133.
[111] With respect to the effect of enemy fire on attack aircraft, the CO, MAG-33 later commented that “Antiaircraft artillery has a direct deterioration effect on pilot accuracy, particularly with regard to care in getting on target and doing a precise job.” CO, MAG-33 ltr to CG, 1st MAW, dtd 25 Jul 52, quoted in PacFlt EvalRpt No. 5, p. 9-76.
On 30 June 1952, the 11th Marines published the SOP. Since the objective was to prevent enemy fire from interfering with friendly strike planes, the key to the entire procedure was the precise coordination of artillery fire with the delivery of aircraft ordnance. As Colonel Henderson described the system:
When the infantry regiment received word of an air strike, the air liaison officer plotted on the map ... the target of the strike, the orbit point, the direction of approach, and the altitude ... and direction of pullout. Then the artillery liaison officer, by looking at the map, could determine which of the Chinese positions could bring effective fire on the strike aircraft. The artillery battalion had prearranged code names and numbers for every antiaircraft position. All the artillery liaison officer had to do was pick up the phone and tell the F.D.C. [fire direction center] ‘flak suppression’ and read off what targets he wanted covered.
These fires were then delivered on the request of a forward observer who was with the forward air controller.... When there was a forward air controller up in the front lines controlling the strike, we would put a forward observer with him. When the planes were ... ready to go, the F.O. [forward observer] got the word ‘Batteries laid and loaded,’ and he would tell them to fire. The minute the FO would get the word, ‘On the way,’ the forward air controller would tell the planes to start their run. As a result, we had cases where the planes were in their bombing run within 30 seconds after the flak suppression was fired, which meant that they were in on the target while the positions were still neutralized. The question of control and split second timing is of exceeding importance because the aircraft are going 300 to 400 miles an hour....[112]