Helicopters draw a lot of attention with their almost magical ability to hover, fly in any direction and operate without runways. They also help save many lives, often dramatically, with their extensive use in all-weather military missions, ambulance duties and search-and-rescue roles.
When things go wrong, dramatic images and news stories about helicopter accidents grab the public’s attention. This is especially true when high-profile celebrities or government officials are involved.
However, modern rotorcraft are safe. Each year, the U.S. commercial helicopter industry flies about 3 million flight hours. There were 0.77 fatal accidents per 100,000 flight hours on average from 2018 to 2022. In comparison, general aviation, which refers to small fixed-wing aircraft and not jetliners, averaged 0.88 fatal accidents per 100,000 flight hours over the same period.
As an aeronautical engineer who specializes in rotorcraft and the director of a national vertical lift center of excellence, I have observed academic, government and industry efforts to improve helicopter safety. A lot of technology and training have gone into making helicopters safe.
Long road to safety
Rotary-wing aircraft were first developed over a century ago. The first that went into mass production was the autogiro, developed in 1923 by Juan de la Cierva in Spain. The pinwheel-like nature of the main lifting rotor avoided the dangers of stalling, which wrecked so many fixed-wing aircraft during that era. Stalling is when the angle of an airplane’s wings relative to the airflow is too great, causing the plane to lose lift.
Within 15 years, the first true helicopters with powered rotors – capable of hovering, low-speed flight and safe descent in the event of engine failure – were in the air in both Europe and the United States. Large-scale military and commercial production began just a few years later during the World War II.
How helicopters fly.
Today’s helicopter operations are anchored on three main principles: comprehensive vehicle design, testing and manufacturing; well-trained flight crews; and thorough maintenance practices. Advanced technology plays a vital role in each of these pillars of helicopter safety.
Safety fundamentals
Helicopter safety begins with the fundamental capability of large-diameter rotors that can auto-rotate in the event of engine failure. With the engine off, the rotors spin freely, slowing the helicopter’s decent and allowing parachute-like controlled landing. Reliable powertrains – engines, gear boxes and driveshafts – long-lived blades and low-vibration airframes have also paved the way for safer flights.
Additionally, advanced autopilot and computer-controlled or assisted flight controls, terrain-avoidance radar and rotor blade deicing systems that enable all-weather flight have become common on modern helicopters. Decades of basic and applied…
