Did some Chinooks become attack helicopters in Vietnam?

Short answer

Yes. In late 1965 Boeing Vertol converted four CH-47A helicopters into gunships, the ACH-47A, with armor, upgraded engines, two 20 mm cannons, a 40 mm grenade launcher in the nose, and five .50 cal machine guns. They arrived in Vietnam in 1966 for six months of operational testing.

Published: October 23, 2026 · Updated: October 23, 2026 · Edited by Above Ten Thousand · Editorial policy

Did some Chinooks become attack helicopters in Vietnam?

Boeing CH-47 Chinook 13Tony Hisgett from Birmingham, UK (CC BY), vía commons

A Heavy Transport Turned Gunship

The ACH-47A was first known as the Armed/Armored CH-47A before receiving the official designation of US Army attack and cargo helicopter. Boeing Vertol converted four CH-47A helicopters in late 1965, adding armor and upgraded engines. The armament was formidable for a helicopter of its time: two fixed forward-firing M24A1 20 mm cannons, a nose turret with an automatic 40 mm grenade launcher, five .50 cal (12.7 mm) machine guns, and two side pods for additional weapons.

Six Months at An Khe

Three of the four aircraft were assigned to the 53rd Aviation Detachment in South Vietnam, while the fourth stayed in the United States for weapons testing. They arrived in 1966 and spent six months of operational evaluation at An Khe Army Airfield. In combat they performed well, but their maintenance was expensive, and the Army needed Chinooks more urgently as troop and cargo transports.

Three Losses and a Nickname

Three ACH-47s were lost. One collided with another CH-47 while taxiing on the ground. Another crashed when a retaining pin on one of its 20 mm cannons came loose and the weapon fired into the forward rotor blades. The third was disabled by enemy fire and destroyed. Unofficially, soldiers called these gunships "Guns A Go-Go." The experiment never went into full production, but it demonstrated the versatility of an airframe designed to move troops, artillery, and supplies.