The AFH-1 Crash Ballistic Protective Flying Helmet, Nylon Outer Shell was studied already in 1962 by the US Army in response to early combat experience in SEA with the APH-5 standard flight helmet.
 
Development and testing lasted until end of 1965, leading to an helmet shell made of ballistic-resistant Nylon fabric, laminated with phenolic resin. The result was a better fitting and bullet-proof helmet, but the weight increased up to 1,5 Lbs. A single dark or clear visor was operated to a classic screw knob.
 
Due to shortages and slow delivery, only about  5000 AFH-1s reached the troops in Viet-Nam by mid 1967, and deliveries were completed by end of 1969.
 
Meantime the APH-5 was still used in combat, although  the US Army declassed  it to the status of  "stateside use only".