Poor execution of autorotation landings, onto rough or too-soft terrain and into objects, accounted for a disproportionate number of injuries and deaths in helicopter accidents last year, according to safety analyst Robert E. Breiling Associates of Boca Raton, Fla. Powerplant, accessory, tail rotor shaft, bearing and gearbox malfunction led to a major portion of those accidents, according to a Breiling report.

Although the number of helicopter accidents in the U.S. last year declined some 10 percent from the year before, the number of fatalities dropped by nearly double that rate, from 41 to 50, while the total number of fatal accidents held relatively steady.
However, twin-turbine helicopter operations saw a nearly two-fold rise in fatalities, even though the number of deadly accidents fell sharply, from 24 in 2003 to just 11 last year. Offshore operations yielded a disproportionately high number of deadly crashes, with 10.