HST-550 Stallion

The HST‑550 Stallion, introduced by Helio Aircraft Company in 2012, represents a pivotal evolution in utility turboprop design. Developed from the earlier HST‑400 series, the Stallion incorporated lessons learned from extensive field testing in remote regions of Africa and South America, where operators demanded a rugged platform capable of handling unpaved strips and extreme weather. Its all‑composite airframe, paired with a 550‑shaft‑horsepower Pratt & Whitney PT6A‑67B engine, delivers a cruise speed of 310 kt and a range of 1,850 nm, while maintaining a short‑takeoff distance of 850 ft at sea level. Key features include a pressurized cabin with modular seating for up‑to twelve passengers, GPS‑integrated avionics, and a reinforced landing‑gear system that tolerates 30 percent higher load factors than its predecessor. The Stallion’s reliability and low operating cost quickly earned it a reputation among charter services, humanitarian NGOs, and government agencies, influencing subsequent designs in the light‑turboprop market. Its introduction marked Helio’s transition from niche bush aircraft to a global contender, underscoring the importance of adaptable, high‑performance platforms in modern aviation. By 2024 the Stallion had accumulated over 45,000 flight hours across more than 120 operators worldwide, and Helio established a dedicated maintenance network in four continents, ensuring rapid parts delivery and continuous airworthiness.