"a precise speed is critical. Just 15 kilometers per hour (9.3 mph) faster or slower and the plane can stall...."
Doomed Flight AF 447: Questions Raised about Airbus Automated Control System - SPIEGEL ONLINE - News - International Question -- at the top of a big storm cell, in that kind of turbulence, isn't the air around the aircraft changing direction faster than plus or minus 15 kph rapidly? what is the aircraft/pilot/computer detecting?