What was the first Army MEDEVAC helicopter?

The first Army MEDEVAC helicopter was the OH-13. This aircraft, commonly known as the Sioux, was used during the Korean War and played a significant role in medical evacuation operations. Its design was particularly suited for aerial reconnaissance and light utility tasks, but it also became instrumental in transporting wounded soldiers from the battlefield to medical facilities.

The adaptability of the OH-13, combined with its agility and the ability to operate in various environments, made it a valuable asset for medical evacuations. The introduction of helicopter-based MEDEVAC fundamentally changed the way military medical care was provided, significantly reducing the time it took to evacuate injured personnel compared to ground transport.

The other options presented in the question represent advanced helicopters with different primary functions. For instance, the UH-60 Black Hawk is widely used today for MEDEVAC but came later as an evolution in helicopter design. The AH-64 Apache is primarily an attack helicopter, while the CH-47 Chinook serves as a cargo and transport helicopter, neither of which were designated primarily for medical evacuation in the same historical context as the OH-13.