The purpose of this investigation is to provide data relevant to the analytical and experimental assessment of the severity of neck system loading induced by the protective and performance enhancing equipment worn by today's aviator.

Mass properties of various head encumbering devices (e.g., helmets, gas masks, night goggles, etc.) have been measured using the automated mass properties measurement system of the U.S. Air Force Armstrong Aerospace Medical Research Laboratory (AAMRL). By using a Hybrid III anthropomorphic manikin head, results were expressed within a standard head anatomical coordinate system.

Dynamic tests were conducted on the Air Force 6-inch HYGE vertical impact facility. The repeatable half-sine carriage acceleration for the tests was a profile of 20 G peak acceleration and 50 millisecond duration. Head encumbering devices were mounted onto the Hybrid III manikin head-neck assembly to evaluate inertial loading effects.

The procedure for measuring the mass properties is presented along with locations of encumbrance centers of gravity, and principal moments and directions defined within a head coordinate system for eight different ensembles. HYGE test results of both unencumbered and eight encumbered configurations are also presented. Comparisons are made between two specific fighter gear and chemical defense configurations.