Determination of head/neck loads during manoeuvring acceleration

Abstract

: Neck injury risk can increase when aircrew wear head mounted equipment while exposed to +Gz-loads. The effects of added weight and change in centre-of-gravity were determined during a centrifuge study using an instrumented manikin at Brooks AFB, Texas. Data included centrifuge Gz, head acceleration (three axes), and head and C7-TI pitch moment, compressive and shear forces. Helicopter (0.5G/s at +1.75 and +4Gz) and tactical aircraft (2Gk and 6GIs from +4 to 12Gz) accelerations were simulated (5s plateau at each level). Effect of added weights (up to overall 2.7kg) were measured in the forward pitch and lateral planes and tested using ANOVA. Seven real helmet systems were also tested. Head Gx and Gy increased with increasing +Gz-load, head weight, as CG shifted in the forward pitch plane, and onset rate. Head Gz was greatest when weight was distributed laterally. The resultant head and neck force and moment increased with increasing weight, pitch angle, and +Gz load. Neck forces and moments were significantly larger than those measured in the head.