AC-123K Black Spot
NC-123K Black Spot

In September 1965, the US Air Force contracted E-Systems of Greenville, Texas to modify 2 C-123B aircraft as part of Project Black Spot. The modifications involved the outfit of the aircraft, serial numbers 54-691 and 54-698, with an advanced sensor suite and weapon system. The intent was to develop an aircraft suitable for counterinsurgency scenarios involving the need for improved means of attacking targets at night. In addition, each aircraft was brought up to the C-123K standard, involving the addition of a podded jet engine slung beneath each wing, which supplemented the original pair of piston engines and improved the performance of the Fairchild tactical transport, which had entered service in 1955.

On 7 February 1966, the US Air Force began Operation Shed Light, which was intended to coordinate developments relating to improving night fighting capabilities within the service. In the first five months of its operation, the Shed Light Task Force identified a total of 9 weapon systems and 77 additional research and development projects that fell under its charter. One of these was Project Black Spot.

On of the end goals for Operation Shed Light was the development of a self-contained night attack (SCNA) aircraft. Initially, the proposed platform for this aircraft was a modified US Navy S-2D Tracker anti-submarine warfare aircraft. The F-111 was also proposed for the role. In January 1968, the USAF issued a stop work order for the YAS-2D after numerous delays and other difficulties. The operational evaluation of the F-111 in Southeast Asia during Operation Combat Lancer had experienced numerous issues as well. As a result, the Black Spot aircraft became prime contenders of the SCNA mission.

E-Systems had modified the aircraft, designated NC-123K in 1968, with a new nose, 50 inches longer than the original, which held a sensor turret. The cargo bay area had also been modified to include an armament system allowing the dispensing of cluster munitions through trap-doors in the aircraft's floor. The sensors fitted to the aircraft included: an Autonetics (A division of North American Aviation) R-132 forward looking radar (FLR), an Avco Forward Looking Infrared (FLIR) camera, a Westinghouse Low Light Level TV (LLLTV; with automatic tracking), and a Westinghouse laser rangefinder. The FLR would be used to locate targets for closer inspection via the LLLTV or FLIR. It was fitted with a Moving Target Indicator (MTI) and automatic tracking capability. Targets located could then be attacked with cluster munitions.

A computer determined the bomb release point, but in Black Spot all the sensors automatically fed data into this device. The cargo compartment contained a dispensing unit, originally designed for possible installation in the bomb bay of a B-47 or B-52 strategic bomber, which held 72 canisters. BLU-3/B (using the ADU-253/B adapter) or BLU-26/B (using the ADU-272/B adapter) bomblets could be carried. The aircraft could carry 74 or 177 canisters depending on the munitions fitted, totaling 2,664 or 6,372 one pound bomblets. The CBU-68/B cluster bomb could also be carried, but there are no reports of this weapon being used operationally from the aircraft. The canisters then dropped through the dispenser's 12 vertical chutes to burst open and scatter the bomblets. Flare launchers were also fitted. These were initially hand held types, but were later replaced by the LAU-74/A automatic launcher.

The NC-123K aircraft were first deployed to meet operational needs as the result of an emergency on the Korean Peninsula. During the tense months following North Korea's capture of the US intelligence ship Pueblo in January 1968, North Korean infiltrators began landing from small boats, bypassing the demilitarized zone that separated South Korea from the communist North. The two NC-123Ks arrived in Korea during August 1968 and remained there for about 3 months, trying to intercept gasoline-powered motor boats. The aircraft met with a certain amount of success intercepting boats at night and the decision was made to subsequently deploy them to Southeast Asia for an operational evaluation.

Between 15 November 1968 and 9 January 1969, the Black Spot aircraft attacked trucks in Laos and enemy river traffic in the Mekong Delta, showing enough promise to cause the Commander in Chief, Pacific Command, Admiral McCain, to retain them until the end of the 1968-69 dry season and use them again when the rains ended in the fall of 1969. In 1969, the aircraft were also redesignated as AC-123Ks. However, the Black Spot aircraft were not like the other AC- designated gunship aircraft, lacking side-firing weapons.

The NC/AC-123K aircraft were subsequently transferred to Ubon Royal Thai Air Base, to position them closer to the Ho Chi Minh Trail, their primary target area. The aircraft were attached to the 16th Special Operations Squadron. Initially escort for the aircraft was provided by F-4 Phantom IIs, but the differences in the speeds of the aircraft made it difficult for the escorting aircraft. Subsequently, A-1 Skyraiders from Nakhon Phanom RTAB provided escort on the 2 missions flown each night by the aircraft.

In May 1969, the 2 aircraft returned to Hurlburt Field, Florida for further modification and refit. At this time, one of the aircraft received the Black Crow truck ignition detector equipment. Additional crews were subsequently trained on the aircraft for missions against the Ho Chi Minh Trail. In October 1969, the aircraft and 2 of the 4 trained crews returned to Ubon to resume operations. The second set of crews arrived in November 1969 and missions subsequently resumed over Laos.

Some idea of the effectiveness of the system could given by the fact that in 141 outings during Operation Commando Hunt III during 1969-70, the NC/AC-123K destroyed an average of 3.12 trucks per mission. Although Black Spot received credit for destroying 1,128 trucks during roughly 14 months of action, the kinds of munitions dropped by the converted transports lacked the punch to cause such havoc. Intelligence analysts may not have realized at the time that the bomblets generally did only superficial damage to vehicles, puncturing tires, gas tanks, and radiators. The fragments might wound or kill drivers, but seldom did the weapons start a fire that consumed a truck and its cargo.

The Black Spot aircraft, moreover, proved vulnerable to antiaircraft fire. The best of the sensors, the infrared detector that scanned ahead of the aircraft, could not locate targets from altitudes above 5,000 feet. This limitation doomed the project, for during 1969 antiaircraft guns capable of reaching this altitude were already appearing along the major roads of southern Laos. "I have concluded," declared General Brown, the Seventh Air Force Commander, in June 1970, "that despite past accomplishment and our need for sensor equipped first-pass-capable truck killers, the AC-123's reduced effectiveness due to vulnerability dictates . . . removal from SEA."

A subsequent attempt to restrict Black Spot to lightly defended routes, relying on the Black Crow sensor to spot trucks through the jungle canopy, ended in failure, for the ignition detector in the AC-123 indicated only the general presence of gasoline engines and could not pinpoint individual vehicles. Along with the success of the AC-130, which spelled the end of more than just the Black Spot program, the combat careers of the 2 prototypes came to a close in June 1970. The 8th Tactical Fighter Wing, which had been the last unit that the aircraft were attached to, recommended canceling the project and preserving one of the aircraft in the Air Force Museum at Wright-Patterson Air Force Base, near Dayton, Ohio.

Official and secondary histories often suggest that the Black Spot aircraft were not intended to be an operational weapon, but were only evaluated as a proof of concept. The usage of the "N" prefix, indicating major, but non-standard modifications, is often used as evidence of this. However, as part of the expansion of capabilities under Operation Shed Light, a total of 20 production Black Spot aircraft were planned, with a total cost of $64.7 million. Conversion of C-130 aircraft to a Black Spot II configuration was also proposed, but the conclusions drawn from the operational evaluation and the changing nature of the operational environment meant that never came to pass.

The fate of the aircraft, which were eventually redesignated back to NC-123K, is unclear. The 2 aircraft are generally reported to have returned to the United States to be stored at Davis Monthan Air Force Base in Arizona where, after 2 years, they were returned to Southeast Asia to be transferred to the Royal Thai Air Force within the agreements of the US Military Assistance Program. It is reported that the aircraft still carried the unique camouflage scheme applied to them for their night operations. This is unlikely, given the nature of the modifications to the front of the aircraft (the reason why the "N" prefix was used initially), though the official description of the NC-123K designation was: "Similar to C-123K but partially demodified from AC-123K (modified to an attack configuration) to permit general cargo handling and troop movement." As the designation "NC-123K" did not only apply to the Black Spot aircraft, its possible that the NC-123K aircraft subsequently sent to the Thai Air Force under MAP were from other programs where the aircraft were less dramtically modified.

In addition, the chronology in the official history of the first deployment notes a "munitions accident" on 19 March 1969, but contains no details of the fate of the aircraft. Anecdotes suggest that one of the aircraft had had its rudder shot off during an operation, causing it to crash land at Ubon RTAB, killing the entire crew and being completely destroyed. If the aircraft had required massive repairs, this could have been conducted during the May 1969 refit. The official aircraft record sheets, however, show both aircraft being sent to Napier Field, Alabama (not Davis Monthan Air Force Base). The aircraft were still reported to be there when they were striken from the rolls in 1972, still listed as NC-123Ks.

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