Hi
Quite simple. Before leaving the gate the Aircrafts take off and climb performance is calculated based on a given flap setting.
As Taxi clearance is recieved from the stand the Captain starts to taxi the aircraft to the runway in use and calls for Flap XX. The First Officer then sets the flaps to the take off position (normally on a 737 this is flap 5).
During the Taxi checklist or Before take off checklist the pilots verify that the flaps are in the correct take off position and that they have all deployed correctly.
Last edited by LAX; 16th Mar 2006 at 19:28.