Description

Line up is a part of the ground movement of an aircraft that normally connects the taxiing phase and the take off roll. It starts when an aircraft moves past the runway holding position of a taxiway and ends when the aircraft gets aligned with the runway centreline.

Essentially, lining up means that the aircraft enters a runway. Once the nose has passed the holding point, the runway is to be considered occupied regardless of the fact that the aircraft may still be on the taxiway.