Quote:
Originally Posted by ghogue  4-1-19. Transponder Operation
3. Civil and military transponders should be adjusted to the "on" or normal operating position as late as practicable prior to takeoff and to "off" or "standby" as soon as practicable after completing landing roll, unless the change to "standby" has been accomplished previously at the request of ATC. |
Unless of course you're flying out of ATL or the other handful of other airports which require your transponder to be on while taxing on the airport.