chris writes:

At a controlled airfield 'rolling' is quite redundant, since before
you can takeoff you must have received a clearance to takeoff and then
have read it back. Rolling is useful at uncontrolled airfields
because there is no ATC, therefore no clearance required to takeoff so
it lets other pilots who might be on downwind or finals know you'll be
off the runway in a few seconds and they will be able to land. At an
uncontrolled airfield I will often make a radio call when lining up
and another for rolling..

Thanks, that seems logical.

--
Transpose mxsmanic and gmail to reach me by e-mail.