Noise Environs and Helmet Performance for the P-1127 V/STOL Aircraft

The purpose of the evaluation was (1) to measure the acoustic noise environment in the cockpit of the United Kingdom Hawker Siddeley P-1127 V/STOL aircraft that would serve as an acoustic guideline for cockpit noise levels of aircraft being contemplated or under construction, and (2) to determine the acoustic attenuation of various Air Force flight helmets in the inventory or being contemplated for Air Force inventory items. Cockpit sound pressure levels in the P-1127 V/STOL aircraft at various engine rpm settings were measured. The cockpit noise environment at maximum engine rpm was reproduced in the laboratory and used to obtain objective attenuation data for three Air Force flight helmet/liner configurations. Measurement of real-ear attenuation at threshold were also accomplished on the helmet/liner configurations. (Author).