What action should a pilot take if they encounter a thunderstorm during flight?

When a pilot encounters a thunderstorm during flight, the safest action is to avoid the thunderstorm by at least 20 miles. Thunderstorms can produce severe turbulence, lightning, hail, and even tornadoes, all of which pose significant dangers to the aircraft and the safety of its occupants. By maintaining a distance of at least 20 miles from the storm, a pilot can avoid the worst effects associated with these formidable weather phenomena.

This distance is particularly important because the strong updrafts, downdrafts, and associated turbulence can extend far beyond the visible boundaries of the storm. Additionally, staying away from the thunderstorm reduces the risk of flying into areas where visibility is severely reduced or where lightning may strike.

In contrast, flying directly through the storm or trying to climb above it without proper knowledge and altitude can lead to extremely dangerous conditions. Taking an alternate route may not provide the necessary clearance from the storm, especially if the storm's boundaries are not clearly defined. Therefore, the advised distance of at least 20 miles ensures that the flight remains safe and minimizes the risks associated with potential storm activity.