Mountain Flying Safety
Microbursts
Microbursts are sudden gusts of unusual strength. They form quickly and catch many pilots by surprise. Microbursts cause serious aircraft accidents without warning.
There are two types of microbursts. Wet and dry microbursts.
You associate the wet microburst in Eastern active thunderstorms with intense rain. The cause, in young thunderstorms, occurs because updrafts are formed when water changes to ice at the freezing level in the atmosphere. In moist regions of the East the air is loaded with moisture. When liquid water goes through a change in state (from liquid to a solid) it releases 540 calories per gram of liquid state water.
When you watch a thunderstorm build, over a period of time, suddenly it seems to explode quickly to thousands of feet in a short time span. The energy released, as water changed from a liquid to a solid (ice), it heats the air and the air rises quickly. This is the updraft phase. As the small ice crystals accumulates more liquid, as it tries to fall back, that friction creates a downdraft. Hail is the final product from the oscillation of the small ice crystals back and forth (vertically) in the growing thunderstorm.
The close proximity of downdrafts and updrafts (microbursts) cause forces that can flip a plane over. Control and recovery are very difficult. The plane may soon exceed its structural limit and come apart in the thunderstorm.
Wet microbursts are phenomenon to avoid.
Why are they so dangerous? They form underneath the thunderstorm in clear air. You don't see them and, without warning, the gust hits you. Damage is done because you haven't slowed the aircraft down to a speed where gusty conditions won't cause structural damage.
In wet microbursts you don't penetrate the building storm. In dry microbursts a pilot is tempted to fly under the storm because of the relatively high ceiling under the storm. Wind velocities of microbursts can exceed the ability of a plane to climb or prevent a rollover if caught between an updraft and a downdraft simultaneously.
Lesson learned is a safe flight only if you respect any thunderstorm.
When you watch a thunderstorm build, over a period of time, suddenly it seems to explode quickly to thousands of feet in a short time span. The energy released, as water changed from a liquid to a solid (ice), it heats the air and the air rises quickly. This is the updraft phase. As the small ice crystals accumulates more liquid, as it tries to fall back, that friction creates a downdraft. Hail is the final product from the oscillation of the small ice crystals back and forth (vertically) in the growing thunderstorm.
The close proximity of downdrafts and updrafts (microbursts) cause forces that can flip a plane over. Control and recovery are very difficult. The plane may soon exceed its structural limit and come apart in the thunderstorm.
Wet microbursts are phenomenon to avoid.
Out in mountainous country the dry microburst is found. The western states are dry so thunderstorms usually have high ceilings underneath.
Why are they so dangerous? They form underneath the thunderstorm in clear air. You don't see them and, without warning, the gust hits you. Damage is done because you haven't slowed the aircraft down to a speed where gusty conditions won't cause structural damage.
In wet microbursts you don't penetrate the building storm. In dry microbursts a pilot is tempted to fly under the storm because of the relatively high ceiling under the storm. Wind velocities of microbursts can exceed the ability of a plane to climb or prevent a rollover if caught between an updraft and a downdraft simultaneously.
Lesson learned is a safe flight only if you respect any thunderstorm.
