Design and development of an automated acoustic based jet engine performance evaluator

Aircraft jet engines produce loud thundering sound that is caused due to high rate of fuel-air combustion. However due to improper combustion caused by non proportional air-fuel ratios, malfunction of fuel feed or any other loose gauging, certain abnormal sounds are produced that indicate fault occurrence. This research is an attempt to automate fault detection in aircraft jet engines by acoustic observations. The experimental analyses were based on sound analysis of Teledyne J 69 Jet Engine. Noise features were identified and extracted for subsequent analysis from frequency spectrums of jet engine audio signals. A total of 100 samples were analyzed for noise feature extraction and a threshold for noise magnitude was empirically found for automated fault noise identification. The developed system was subsequently tested over 400 audio samples from 40 different engines of Teledyne J 69 type that resulted in the system´s accuracy of 97%.