Aircraft pitch and roll angle play a huge role in the trajectory of the seat upon ejection. That combined with sink rate and low altitude (50 ft AGL is very low) can put the seat outside safe ejection envelope. That does not mean the seat failed to function in any way, but that the velocity vector present at the time of ejection meant that the seat did not have the ability (energy potential) to prevent impact with the ground shortly after rocket motor burn out. Basically, an ejection seat has a fixed amount of energy in the rocket motor. If the energy required to change an unsafe velocity vector into a safe velocity vector exceeds the energy available, the ejection is outside the envelope of the seat.
Other factors (not present here) include airspeed and altitude. If flying at high speed upon ejection the seat may function just fine, but the pilot might not survive the resulting airblast. Flailing injuries can result, and those injuries may be fatal. At very high altitude the seat may also function just fine, but the pilot may not survive the outside environment (very cold and very thin air.) So an airplane may be able to supercruise at 60K, but what happens if the pilot has to eject during such a supercruise?
Last edited by KenV; 29th Jul 2015 at 21:10.