The US Air Force's AC-130 gunship has a reputation for delivering firepower to the battlefield.
Two AC-130Js used a more subtle tool to aid US forces on the ground during the evacuation of Kabul.
As US troops and their partners withdrew, the gunships kept watch with their "green beams."
The AC-130 is one of the US military's most capable aircraft. Ground troops love the gunship and the capabilities it brings to the fight, but it can be effective even without deploying its large arsenal.
During the chaotic evacuation of Kabul in August 2021, two AC-130J Ghostrider crews used a little-known laser sensor on their planes to help control the chaotic situation around the airport and keep enemy forces at bay as friendly troops carried out the evacuation.
The crews, both from the 73rd Expeditionary Special Operations Squadron, distinguished themselves during the operation and received the Mackay Trophy for the year's most meritorious flight, Lt. Gen. Jim Slife, commander of Air Force Special Operations Command, said in September.
The green beam
While discussing the performance of Air Force special-operations crews during the Kabul evacuation, Slife referred to a targeting technology that Air Commandos use and affectionally call "the green beam."
AC-130 crews use the green beam - which Slife called a "giant green laser pointer" - both to point things out to friendly forces and to deter adversaries by letting them know that they're in the gunship's sights. AFSOC started putting the laser on several of its aircraft around 2010.
The heavily armed AC-130 usually operates at night because its bulky size and need to fly relatively low and slow to fire accurately make it more vulnerable than other aircraft.
Using the laser has some downsides - mainly that it reveals the gunship's position, making it easier to target from the ground.
The laser is meant "to let the adversaries know that you see him," Slife said at an event hosted by the Air and Space Forces Association. "So it's not a particularly popular capability among the crews, because the other end of that green beam is connected to me and I don't necessarily want to highlight my position like that."
During the chaotic evacuation, AC-130 gunships and AH-64 attack helicopters provided air cover for troops on the ground, who had the challenging mission of evacuating tens of thousands of people who crowded the airport to escape the Taliban.
During the evacuation, AC-130J crews used their green lasers, which are visible to the naked eye, to illuminate people who breached the Kabul airport compound, allowing ground forces intercept them or drive them off.
The green beam proved extremely useful for "managing a very chaotic situation on the ground," Slife said, adding that gunship crews used it to communicate with ground forces about potential threats, thereby "building the situational awareness for the force on the ground and keeping the adversaries kind of pushed back while the evacuation was underway."
While flying at night, it's very useful to have aids to see where exactly you are aiming, and the AC-130 has other laser-targeting and range-finding sensors to aid in the crew's marksmanship.
Hitting something is not as simple as seeing it, since gravity, elevation, speed, and atmospheric conditions affect the trajectory of the AC-130's artillery and cannon fire, but having those aids is still invaluable for gunship crews.
The AC-130 gunship
In addition to being heavily armed, the AC-130 can remain over the battlefield for long periods, though its dwell time is limited by the cover of darkness and other conditions. Those features have made the gunship one of the most celebrated and highly valued aircraft by among ground troops.
The AC-130 is essentially a precision artillery gun on wings. It carries deadly 105 mm and 30 mm cannons, AGM-114 Hellfire air-to-ground missiles, GBU-39/53 small diameter bombs, AGM-176 Griffin precision-guided glide bombs.
Air Force Special Operations Command has been experimenting with other weapons for the gunship, including a high-energy laser that could allow it to carry out stealthier ground attacks and to defeat incoming missiles.
To engage its targets, the AC-130 employs the "pylon turn" technique in which it flies in a wide, steady turn, allowing its gun crews to fire away while aiming at a fixed point on the ground.
The AC-130 has been around since the Vietnam War and has been so successful that the Air Force continues to upgrade it. Since the AC-130A was introduced in 1968, US crews have flown the -E, -H, -U, -W, and -J versions. The latest version, called Ghostrider, was introduced in 2017 and saw extensive combat in Afghanistan.
Stavros Atlamazoglou is a defense journalist specializing in special operations, a Hellenic Army veteran (national service with the 575th Marine Battalion and Army HQ), and a Johns Hopkins University graduate. He is working toward a master's degree in strategy and cybersecurity at the Johns Hopkins' School of Advanced International Studies.