A new generation of U.S. Army flight helmets.

Head injuries are the most common cause of fatal injury in helicopter crashes. For over 80 years, the U.S. Army has used crash investigation studies to redesign flight helmets. This paper describes the evolution of the new fielded U.S. Army helmet, the Sound Protection Helmet No. 4B (SPH-4B), and compares its protective features to its predecessors, especially the SPH-4. A major contribution to the helmet design process was made by the Aviation Life Support Equipment Retrieval Program (ALSERP), a functional program at the U.S. Army Aeromedical Research Laboratory (USAARL). ALSERP has analyzed more than 500 helmets involved in crash events since 1972. Based on these studies of critical safety factors, the Army has developed and deployed the SPH-4B, a new helmet with improved energy absorption, retention, and stability.