Another key factor in the defense of Khe Sanh was the manner in which Lieutenant Colonel Hennelly's FSCC coordinated their air effort with the artillery so that the two components were complimentary. One prime example was the Mini-Arc Light which was devised by the Assistant Fire Support Coordinator, Captain Kenneth O. W. Steen and the TIO, Captain Baig. As the name implies, this technique was used against an area target the same as a B-52 strike, only the former could be organized and employed much quicker. When intelligence reports indicated that NVA units were in a certain region, the FSCC plotted a 500 by 1,000-meter block in the center of the suspected area or across a likely route of march. Two A-6 Intruders, each armed with 28 500-pound bombs, were called on station for a TPQ and the batteries at Khe Sanh, Camp Carroll, and the Rockpile were alerted for a fire mission. Thirty seconds before the two A-6s dropped, the 175mm batteries, concentrating their fire on one half of the block, salvoed the first of approximately 60 rounds. At the same time the A-6s rippled their load down the middle of the block, the 1/13 batteries opened up on the second half with around 200 155mm, 105mm, and 4.2-inch rounds. The trajectory and flight time of all ordnance were computed so that the bombs and initial artillery shells hit at the same instant. The saturation of the target area was such that any enemy soldiers caught in the zone during the bombardment simply ceased to exist.(158) During the second week in February, a special Mini-Arc Light was directed against a major NVA headquarters. Two members of the 26th Marines S-2, Majors Robert B. Coolidge and Jerry E. Hudson, learned from their various sources that a force-wide meeting of NVA commanders and their staffs would occur in an abandoned schoolhouse near the Laotian border. A beefed-up Mini was prepared to welcome the delegates. For this strike, the target block was reduced to 500 by 300 meters around the schoolhouse which would take in, as one of the planners stated, "the hangers-on and other idlers who usually congregate around large staffs." Twenty minutes after the meeting was scheduled to start, the trap was sprung. Two Marine A-6 Intruders and four F-4B Phantoms unloaded 152 500-pound bombs into the block in concert with the opening volleys of eight artillery batteries (total of 350 artillery rounds).(159) The target was obliterated, but whether or not this unusual ambush netted any NVA brass-hats was never ascertained.