Method for determining pilot stress through analysis of voice communication.

Factors inherent in aircraft communication systems hinder customary approaches to voice analysis in the determination of the degree of stress experienced by a pilot during an inflight emergency. By means of a sound spectrogram, the mean vibration space of a voice can be analyzed if the space between the vertical deflections of the vowel sounds is calculated in micrometers. The vibration space shift rate (VSSR) is calculated by comparing the widest vibration space of the voice during the normal phase of the same flight (standard vibration space: SVS) with that encountered during the emergency situation (EVS) by the following formula: VSSR = ((SUS-EVS)/SUS) X 100%. The number of measuring points in each case differs in regard to the length of communication during the emergency. The VSSR can be divided into three phases - normal, urgent, and emergency - each with three grades of 0.5 S.D. apiece.