sentence: While the ASTB evaluates many skills necessary to aviation , and it is correlated with performance , it does not account for the natural genetic variation in physiological stress response.Once selected by the ASTB , all trainees undergo water survival training in the Modular Egress Training Simulator ( METS ) device ( “ helo-dunker ” ) — an underwater crash simulator that requires trainees to experience a water “ crash ” and perform an underwater egress while blindfolded .