Seasonal and Segmental Variations and Peaks in Aircraft Engine Exhaust Gas Temperature

This study emphasizes comparative analyses across seasons, altitudes, and flight segments, providing insights into how environmental (e.g., outside air temperature) and operational variables (e.g., flight segments, altitude, departing airport) influence Exhaust Gas Temperature (EGT) trends. A large dataset of Quick Access Recorder (QAR) data was used with a focus on winter and summer seasons. Additional analysis concentrated on critical operating points, including ground idle EGT and peak EGT. Pairwise correlations between EGT and related engine parameters were also computed. Engine manufacturers generally report a 3 degrees C increase in EGT for each degree increase in ambient air temperature. For mid-aged engines, this study identified a similar relationship (i.e., 2.4-2.8 degrees C vs. 3 degrees C). The influence of the altitude of the departing airport was also explored, particularly at the highest (peak) and the lowest (ground idle) power settings. Results also reveal the increased risk of losing the EGT margin during takeoffs at high-altitude airports, particularly during the summer season, highlighting a factor that, if not already considered, may require consideration in operation planning. Overall, the mean EGT values of summer flights were found to be 6-9% higher compared to winter, depending on the flight segment. The peak EGT values were identified exclusively during climb segments, primarily concentrated in three altitude regions. Cruise EGT values were found to be sensitive to altitude, exhibiting a tendency for higher EGT values with increasing altitude.