On a clear sky, planes can be seen leaving a white trail behind them when they are in the sky. This trail is quite normal and an event that occurs on most flights. These traces are called “contrail”. The name Contrail has emerged as an abbreviation of the words “condensation” and “trail”.
What is the Reason for these Trails?
Airplanes fly very high. After the 25 thousand feet level is passed, the air reaches -40 C levels, it can drop to -50 from time to time.
Exhaust gas is produced due to fuel consumption at this low temperature. When this gas is expelled, it meets the cold air and condenses and turns into ice crystals.
These white cloud-like traces are formed when the gases resulting from the fuel consumed suddenly meet with the cold air.
This is the same phenomenon as exhaling in cold air leaves a trail of white vapor or white smoke coming out of car exhaust in winter.