ANVIS Compatibility with HGU-56/P Helmet

Physical compatibility assessments of the Aviator Night Vision Imaging Systems (ANVIS) were completed on subjects wearing the HGU-56/P. Data were obtained from 172 subjects participating in a helmet fitting study. Subjects were fitted with the HGU-56/P developer- recommended helmet size based on head length and up to two additional sizes (smaller and larger). On several subjects, compatibility assessments included the M-43A1, type 2, protective mask. Additional measurements of minimum ANVIS eye clearance using rigid head forms were taken to compare with similar data obtained from the subjects. Our results indicate (1) most subjects achieved acceptable ANVIS mechanical compatability and acceptable eye relief while wearing the HGU-56/P, (2) placement of the ANVIS mount higher on the visor cover will increase compatibility, (3) fitting one size larger than the developer-helmet size probably will be required to achieve acceptable and comfortable fit while wearing the protective mask.