|Project Black Spot NC-123K
When it was realized that interdiction of the nighttime movement of supplies along the Ho Chi Minh Trail was the best way to stop the flow of materiel to the Vietcong in the South, the USAF in February 1966 established Operation Shed Light to pool together research efforts and various subprojects into improving the night fighting capabilities of the USAF in Vietnam. Projects Red Sea and Lonesome Tiger belonged to a series of experiments using Douglas AC-47s and Douglas B-26K Invaders equipped with FLIR. Tropic Moon I concerned the use of a low-light television camera (LLTV) to seek out targets at night. A Douglas A-1E Skyraider flew with the Tropic Moon I package, becoming the first aircraft to use a self-contained night attack system in combat.
Tropic Moon II was the modification of three Martin B-57 Canberras into night attack configuration and Tropic Moon III was a further development that involved the modification of 16 Martin B-57Gs with more sophisticated attack avionics.
Briteye was a new battlefield flare that could be used to illuminate the target area and that led to the BIAS (Battlefield Illumination Airborne System) that used 28 xenon arc lamps in a Fairchild C-123K's cargo compartment to produce daylight conditions in an area 2 miles wide from 12,000 feet. Also used on the Lockheed C-130 Hercules, unfortunately BIAS gave enemy anti-aircraft gunners a nice bright target at night.
Operation Shed Light identified the need that a night attack aircraft be completely self-contained and autonomous but had to be large enough to carry the heavy electronics of the day. Initial aircraft candidates were the McDonnell F-4 Phantom, Martin B-57 and Grumman OV-1 Mohawk. There were too few B-57s to spare, the F-4s were already heavily committed and the Air Force didn't want to stoke interservice rivalries by selecting the Army's OV-1 Mohawk. The General Dynamic F-111 was considered the most ideal, but at the time the aircraft wasn't yet operational so the study group next looked at the North American OV-10 Bronco, but it didn't have the load carrying capability.
The most ideal aircraft at the time was considered to the be the Navy's Grumman S-2 Tracker ASW aircraft- it already had a large weapons bay, it was twin-engined, could operate at low level as that was its natural regime when hunting submarines, and it also had good endurance and had a built-in search light. The aircraft was to have been designated the AS-2D and eventually the AS-2D had to be cancelled in 1968 due to difficulties with funding the modifications and problems in getting S-2 Trackers from the US Navy.
Desperate for a platform the Shed Light group turned to a low-level project initiated in 1965 called Project Black Spot which was to use a modified Fairchild C-123K as a self-contained night attack aircraft that instead of bombs or guns, dropped cluster submunitions from chutes in the fuselage. The first Black Spot aircraft, designated NC-123K, began evaluations at Eglin AFB in Florida in 1968 and after some initial trials in Korea to see if its night vision equipment could spot North Korean infiltration teams using boats, debuted in Vietnam operationally in November 1968.