Kopp-Etchells Effect: The Phenomenon That Keeps Planes Safe

When you look up in the sky and see a commercial airplane flying high above, have you ever wondered how it manages to stay on course and avoid obstacles, especially during night flights? The answer lies in a lesser-known phenomenon called the Kopp-Etchells Effect. In this blog post, we will delve deeper into what it is and how it contributes to safe aviation.

 

The Kopp-Etchells Effect, named after the two researchers who first observed it in the 1930s, is an optical phenomenon that occurs when an aircraft's lights reflect off ice crystals present in the atmosphere. These ice crystals are usually found in clouds and are the same ones that cause the shimmering effect on the wings and engine of an airplane, commonly known as "wingtip vortices."

 

The Kopp-Etchells Effect causes the airplane's lights to appear to be refracted or bent, making them appear higher than their actual position. This effect is most pronounced when the aircraft is flying close to the ground, and the angle of incidence of the light is steep. The effect can be observed both in visible and infrared light and can provide pilots with an extra layer of safety during night flights.

 

One of the primary applications of the Kopp-Etchells Effect is in the safe navigation of aircraft during low visibility conditions. When flying in areas with low cloud ceilings, fog, or other weather conditions that reduce visibility, pilots rely on their instruments to maintain course and avoid obstacles. However, in some situations, the Kopp-Etchells Effect can help pilots identify the position of obstacles that may not be visible on their instruments.

 

Plane At Night

 

For example, during a night flight over a mountainous region, the Kopp-Etchells Effect can help pilots identify the position of peaks and ridges, which may not be visible on their instruments due to the lack of ambient light. By observing the refraction of their lights, pilots can estimate the position and height of these obstacles and adjust their flight path accordingly.

 

Another application of the Kopp-Etchells Effect is in the detection of other aircraft in the vicinity. When two aircraft are flying towards each other, their lights can appear to merge, making it difficult for pilots to gauge the distance between them. However, by observing the refraction of the lights due to the Kopp-Etchells Effect, pilots can estimate the distance and position of the other aircraft accurately.