An H-25A Piasecki helicopter has been employed in recreating a “typical” accident occurring with both longitudinal and vertical velocity components at impact. Acceleration patterns at various stations in the aircraft and in the dummy occupants have been found to be incomparable with the results of similar tests conducted for fixed-wing aircraft by NACA. For the helicopter, large magnitude, short duration, accelerations have been observed. By contrast, accelerations of smaller magnitude but with relatively longer duration were found for transport type aircraft by NACA. When the acceleration environment for the H-25 is compared with known tolerance limits for human subjects, the need for modification in crew and passenger seats to provide better crash protection for the aircraft’s occupants becomes apparent.
