Known by Helio as the model H-500 this STOL aircraft mounted twin Lycoming engines on top of the high-set wing, close to the fuselage. With the engines mounted in this manner, lateral and over-the-nose visibility were much improved while the propellers were kept clear of cabin doors and away from possible debris damage during rough field operations.
Much of the aircraft structure was based on the Helio Stallion, a single-engine turboprop version of the more successful Helio Courier.
The Twin Courier could seat six and first flew in 1960, being awarded FAA certification in late 1963. Only seven examples were built, these receiving the United States Armed Forces designation U-5A. One was reported to have been evaluated by US Army Special Forces.
Fully automatic full-span leading edge slats were fitted along with high-lift flaps.