The first reason why the spirals are painted white in aircraft engines is to ensure the safety of airport employees. With the rotation of this spiral, it can be easily understood whether an airplane’s engine is currently running or not. It is not always possible to determine this by sound, because airport workers wear hearing protection and several engines can run at the same time.
Being close to a running aircraft engine is very dangerous. This is because objects up to 4 m in front and 1.5 m on the sides can easily enter this engine.
The second reason for applying such an unusual pattern is protection from birds. In 1986, ANA (All Nippon Airways) conducted an experiment and its results showed that airplanes with spirals in their engines collided with birds nine times less. True, though, some experts were quite skeptical about the results of this experiment.
Source: Ferra
