Measurement of head acceleration and angular rate experienced by aerobatic pilots
Background: Aerobatic pilots are exposed to high levels of positive and negative G’s which can be associated with career-limiting neurovestibular effects including “the wobblies.” Extensive research has been conducted on the effects of positive G’s in centrifuge experiments. Gz tolerances have been quantified for gray-out, black-out, and G-LOC. G-induced vestibular dysfunction or “the wobblies,” though not yet well studied, is thought to affect many aerobatic pilots who are exposed to high levels of negative G’s. Neurovestibular symptoms induced during flight can increase the risk of loss of aircraft control. The actual G forces experienced at head-level in aerobatic pilots have never been characterized, and this study intends to solve this knowledge gap. Methods: Five volunteers at the 2009 US National Aerobatic Championships were fitted with tri-axial accelerometer and angular rate earplug sensors. A second tri-axial accelerometer and angular rate sensor package was fixed to the plane. For each subject, data were collected from the two synchronized sets of hardware during a 10-minute practice session. The recordings of the maximum and minimum G values were also obtained from the aircraft’s G-meter. Results: The maximum and minimum values obtained from the sensors measuring linear acceleration and angular rates from the pilot and the plane were well-correlated. Paired t-tests demonstrated no significant difference between head-level and plane mean linear acceleration. Angular velocity means were mixed. The Gz accelerometer values of the pilot and the plane correlated very closely with the plane’s G-meter. Conclusion: Aerobatic pilots experience a large range of positive and negative accelerations, which appear to correlate well to those of their aircraft. Data can be successfully collected and correlated using tri-axial accelerometers and angular rate sensors. Future work in this field may involve clinical modeling of G-effects based on head-level accelerations and angular rates.