AC-130U Plus 4 / AC-130U+4

In late December 2001, a Department of Defense Program Budget Decision called for purchasing at least 8 additional AC-130U Spooky gunships, and initiating work on a possible replacement AC(X) gunship aircraft. The USAF was directed to purchase and field 4 additional AC-130Us in FY03 and to convert a further 4 C-130H transport aircraft to the AC-130U configuration. Such a conversion required the addition of the AC-130U's armaments, to include 40mm and 105mm cannons, as well as enhanced self-protection systems. To replace the C-130Hs that would be converted, the the Air Force was directed to buy 4 more C-130J transport aircraft than previously planned in FY03. Conversion of the C-130H to the AC-130U gunship (aka AC-130U+4) cost in the range of $50 million to $80 million.

In 2007, the AC-130U Plus 4 program concluded delivery of 4 new gunships. These highly modified C-130s were built as clones to the existing AC-130Us, with the exceptions of obsolescence and integration of the Bushmaster Mk 44 Mod 0 30mm cannon. The contract for the AC-130U Gunship "Plus 4" program had been awarded on 23 January 2003. In order to complete production costs (spares, trainers, etc) of the new 30mm gun, development of enhanced survivability systems was delayed. Enhanced survivability schedules were incompatible with the Plus 4 production schedule. The AC-130U Plus Four primarily used competitively selected prime contractor under the Integrated Weapons System Support Program. Individual acquisition strategies were developed for each project. The AC-130U was logistically supported at organizational, intermediate and depot levels.

The 4 aircraft help relieve the pressure on the squadron's aircraft roster for daily functions such as pilot proficiency training, limited tactical training and daily training flights in conjunction with the 19th Special Operations Squadron. The addition of the aircraft increased sortie and training production at home station allowing us to build more crews and better absorb the high operations tempo down range.

The new aircraft featured 2 Mk 44 Mod 0 30mm cannons to replace the existing 25mm GAU-12/U cannon and 40mm Bofors L/60 cannon, both of which had been a part of the AC-130U's firepower since its inception. The 30mm Mk 44 Mod 0 Bushmaster cannon provided improved maintainability and lethality for the gunship. It was initially installed on Plus-4, with delivery of these aircraft in FY06, with the planned installation across the rest of AC-130U fleet by FY07.

Another improvement for the AC-130U arsenal under consideration was the addition of another precision-guided missile, giving the gunship a precision strike capability. The weapons system was the most significant advancement in recent AC-130 development because it took the platform from being an "accurate" weapons system to a "precision" system, which was important to the type of war the US was fighting in 2007. The changes in the weapons systems affected not only the fire control officers, but every crew position on the aircraft. Everyone would be trained on how the airplane would operate differently and how to plan and execute missions.

A lesser known, yet almost revolutionary change for the AC-130U Spooky was the installation of a "fusion ball", which was a combination of an all light-level television and an infrared sensor. This combination sensor allowed the crew to take the best attributes of both systems and use them simultaneously as they decipher the battle space below them. It had been a long road for this system. This gave a tremendous improvement in the ability to see the environment below us. This system was essential for improved positive identification of targets and friendly forces.

Finally, the AC-130U Spooky gunship had taken delivery of a digital video recording system versus the old VHS tape style it used to employ. This new system allowed a clearer and faster transfer of information to those who needed it, whether in combat or training missions. The digitization also made storage of these recordings easier in the 4th Special Operations Squadron library.

In 2008, the USAF canceled the integration of the 30mm Mk 44 Mod 0 cannon onto the AC-130U aircraft, citing issues with the systems accuracy. While the 40mm Bofors L/60 guns were returned to the aircraft, a shortage of GAU-12/U components meant that these weapons were not refitted.