Thanks, Lou. Many people, some flyers, don't realize the amount of residual energy that is left in the air after an airplane bores a hole in it. Depending on temperature, wind flow, and thermal activity, vortices and rotors can hang around for minutes at ground level. I saw a young pilot get killed when he flew through the wake and standing vortex left by the first 747 after it made a low level pass and sharp pull up at the Abottsford airshow. The previous year at that airshow , the CAF -101's made a near sonic low level pass on after burner that left an audible swirling and wailing in the air for at least 5 minutes. I found out twice that big airplanes work a lot of air and leave a messy wake that one should not fly through.
