I did a search so apologies if asked...
I notice on the A319/20/21 and so on, ding immediatly after take-off.
I'm sure it's when the landing gear is being retracted/extended.
Just wondered why the ding.
Cheers
Stu...
http://flightlevel350.com/Aircraft_A...-4633.html?s=y
Just found this video. You can hear the noisey landing gear retract straight after the ding.