What causes radio interference related to precipitation static on aircraft?

Radio interference related to precipitation static on aircraft is primarily caused by corona discharge emitted from the aircraft. When an aircraft flies through precipitation, such as rain, snow, or sleet, the moisture in the air interacts with the aircraft's structure, leading to the accumulation of static electricity. This static charge can reach a point where it discharges, known as a corona discharge, especially at sharp edges and protrusions on the aircraft.

This phenomenon generates electromagnetic interference, which can disrupt radio communications and navigation signals, impacting the aircraft's avionics systems. The nature of the discharge creates a wide range of frequencies that can interfere with the aircraft's radio equipment, leading to noise in the audio and possible degradation of the signal quality.

In contrast, factors such as excessive weight, corrosion of circuit components, or low battery voltage do not directly relate to precipitation static or the mechanism of corona discharge. Therefore, it is the corona discharge during precipitation that is the key factor causing radio interference in this context.