British firm QinetiQ has adapted its modular vehicle/aircraft composite armor system to protect AC-130J gunships. These four engine aircraft often come down low to use their sensors and weapons in support of ground troops. Until recently this was only done at night, but now the gunships sometimes appear in daytime. There has always been some risk of damage to American gunships from rifles and machine-guns (especially the larger 12.7mm and 14.5mm ones), especially if the bullet his one of the crew or a vital component. The QinetiQ LAST Armor system depends on two techniques to give maximum protection with minimal weight from this kind of threat.
The most critical technique is to use an old World War II solution for protecting bombers from the effects of anti-aircraft fire (mainly the shell fragments). The American and British researchers used the newly developed operations research to come up with a practical solution. Aircraft that returned from these missions were examined and the location of all damage was noted. Then the locations were counted and a drawing of the bomber type made with the damage locations noted. The armor was placed in those locations where there was no damage as that’s where shell fragments obviously hit in all the thousands of bombers that were shot down. So with less than a ton of armor per aircraft, losses were noticeably reduced. The QinetiQ developers used similar operations research techniques, including analysis of what types of projectile (caliber of the bullet or weight of shell fragment) hit where and what damage was done. The armor panels are placed where they would do the most good.
The second difference is that the LAST armor is not metal (like the World War II stuff) but lighter (and more expensive) composites. This stuff provides the same protection at half the weight. Thus a square meter of composite armor weighs 37 kg (81.4 pounds or 8 pounds per square foot).
Like the LAST vehicle armor, the C-130 aircraft version is designed to be quickly attached. More, or less, armor can be installed, depending on what type of threat is expected. In many combat zones the enemy has few, if any, heavy (12.7mm and 14.5mm) machine-guns. This means the gunships can reduce the weight of armor to be carried and the time involved in installing and uninstalling it. The weight is important and it has an impact on how long the aircraft can stay in the air. Gunships are useful in large part because they can stay in the air for a long time (usually over eight hours per sortie).
This LAST armor has already been used in helicopters and larger transports like the C-141 and C-17. Gunships first appeared, using World War II era C-47 transports, in the 1960s, over Vietnam. The troops called the gunships, which liked to operate at night, "Spooky." After Vietnam larger C-130 aircraft were used for gunships and the new C-130J is the latest version of the 1950s transport design to serve as gunships.