Each in-service aircraft is struck by lightning at least once per year, on average. Even if the level of energy of lightning strikes is high, their effects on an aircraft are limited.This article explains the lightning phenomenon and why aircraft are prone to lightning strikes. It describes how aircraft are designed to limit the effects of a lightning strike and ensure that the safety of the flight is not impaired. It also recalls several safety precautions to take in flight and on the ground, and what must be done when an aircraft is struck by lightning.