Biodynamic Assessment of Pilot Knee-Board Configurations During Simulated T-38 Catapult Acceleration

The Aircrew Biodynamics and Protection ABP Team of AFRL 711 HPWRHCPT and their in-house technical support contractor, Infoscitex, conducted a short series of tests to support an objective analysis of determining injury risk to a pilot ejecting from a T-38 with current or proposed kneeboard technology. This effort was initiated to provide data to assist with ejection injury analysis in order to assess if there is additional risk associated with the proposed electronic kneeboard configuration compared to the paper kneeboard configuration. The proposed kneeboard configuration consisted of an Apple iPad Mini with a shock case. The T-38C ejection pulse was simulated using the Vertical Deceleration Tower VDT set-up with a Martin Baker Mk series ejection seat, and the pulse characteristics were determined based on measured seat pan accelerations recorded during the seat testing with both small and large manikins. The USAF currently accepts up to a 5 risk of injury to the spine during the catapult phase of ejection therefore, this injury risk was also used for the kneeboard configuration comparisons. Data from the test series indicated the risk of using either kneeboard configuration paper or EFB was below 5 regardless of the size of the occupant. In general, the data indicated that larger occupants were at a lower risk than the small occupants with the larger occupants having a risk of femur fracture in the 2 to 3 range, and the small occupants having a risk of femur fracture in the 3.5 to 4.5 range. This was most likely due to the small occupants being exposed to a greater catapult acceleration based on the current seat installed in the aircraft. The observational data indicated that the current Velcro strap and the Buckle Clip Strap may not sufficiently support either kneeboard configuration regardless of occupant size however, the larger occupant had issues with both configuration in the this test series.