QUESTION: What is wind shear, and how can it affect me during flight?
ANSWER: Wind shear is a rapid change in wind speed and/or direction. There are several causes, including temperature inversions, frontal zone passages, and thunderstorm activity. Wind shear can happen at any altitude; however, one of the most dangerous times to encounter this phenomenon is during the landing or takeoff phase when the aircraft is at a low altitude and low airspeed.
An extreme type of wind shear is a microburst. Microbursts are small-scale intense downdrafts that spread out in all directions once reaching the ground. This causes both vertical and horizontal wind shear that can be particularly dangerous to aircraft, especially at low altitudes. An encounter like this during landing might exceed an aircraft’s ability to maintain a stable descent rate, causing it to impact terrain short of the runway.
To learn more about this potentially hazardous weather condition, read “The Weather Never Sleeps: Ill Wind” ( http://flighttraining.aopa.org/magazine/2003/June/200306_Departments_The_Weather_Never_Sleeps.html?WT.mc_id=100409epilot&WT.mc_sect=fex ).
Marin County 99s 