I was right out of pilot training, F-4 training, and then off to Korat RTAFB for my combat tour in 1971. I started with missions in Laos dropping where the FAC told us to. Not very rewarding (mainly turning trees into toothpicks. However in the last half of my tour during the dry season I flew 91 night missions flack suppression escorting AC-130 gunships along the Ho Chi Min trail which was a lot better mission. We would be a flight of two but would takeoff independently with on plane heading for the AC-130 and the other going to the tanker. We would rotate between the tanker and AC-130 over about a four hour time frame.
The mission consisted of flying at about 12,000’ with the AC-130 at about 10,000’. We would fly pretty slowly at about 300 kts. in an orbit outside the gunship’s orbit. The way we tracked the AC-130 was by three small lights on the top of its wing put there for that purpose. Everything else was blacked out and of course we flew lights out in the target area. It was interesting keeping track of the gunship as its turn rate in the orbit was higher than ours and we would occasionally loose the tracking lights and would have to guess where it was in its orbit.
We were usually armed with two M36E2 weapons and six CBU-58s. The M36E2 was an old weapon that resembled a 50 gal. drum (with a drag index to match) weighing about 750 lbs. It was filled with 136 thermite bomblets that would burn for a long time. In addition to trying to hit the target with them, they also provided a much needed ground reference. We tried to drop one of the M36E2 during each escort period so that we could have that ground reference for the other aircraft to find us during our rotation to the tanker. The CBU-58 contained a grapefruit sized bomblet and the canister was fused with an FMU-56 radar fuse set to open the canister at 1,500 ft. which provide a good coverage.
When the guns fired at the AC-130 we would track the tracers (could usually tell the caliber of the gun by the number of rounds it fired) and estimate about 100’ down the trajectory to allow for the tracer ignition time. We would call “bulls-eye” so the AC-130 would stop shooting since we would be inside its target area. Then roll in and I would try to keep the approximate target point as I put the pipper on the target. Then as we pulled off the target we had to estimate the AC-130’s position to avoid a mid-air. Fortunately the F-4E had an early version of an automatic release using the radar to input range and a computer calculating the release point based on our trajectory. It wasn’t quite as accurate as the current systems but it was a lot better than a manual release, since it was a dark as being in a cave with no ground references most of the time.
As I mentioned we had to estimate the position of the gunship during our pull-out. One night I had just lost the AC-130 in its orbit when a gun came up. I rolled in on the gun and then I estimated where the gunship was and eased off on my pull-out to miss it. Well I estimated badly and as I came off target this really large black aircraft filled my wind screen; I must have missed the gunship by about 50’. The AC-130s flew with the ramp down and a guy hanging out the back to spot for AAA fire and when I finally got back into my orbit the gunship copilot called me to say I scared the sh*t out of the scanner during the pull-out (I didn’t tell him I had scared the sh*t out of myself).
The other issue was keeping track of the terrain as the AC-130 traveled down the trail as the elevations changed a lot and the karst outcroppings could be pretty steep and the trail generally followed the valleys. I had a good friend that flew into the ground on one of his night missions, probably because he and the WSO lost track of the terrain.