Unusual ground noise following A320
Hi,
The following is a consistent noise that I hear from Jetstar (Australian domestic/international carrier) A320's approaching to land at Sydney airport.
Practically any Jetstar A320 (and possibly all other A320's) coming in to land at a height of about 500m is trailed by an unusual ground noise. The ground noise is the sound of a jet/vortex that trailing the plan some 20 - 30 seconds after it has passed. When I first heard it I thought it was a high speed fighter jet flying overhead, although it is never that loud. The noise seems to be greater in cloudy weather.
I have tried to look for an explanation on this one on the net but with luck. Anyone know what this noise is and why its only from the A320's?