Under what condition should an aircraft not be authorized to LUAW?

An aircraft should not be authorized to Line Up and Wait (LUAW) if the departure point is not visible from the tower. Visibility from the tower is crucial for maintaining situational awareness and ensuring safe operations on the runway. If controllers cannot see the aircraft's position and potential conflicts with other traffic, it increases the risk of accidents or misunderstandings regarding the aircraft's status.

For effective traffic management and safety, it is paramount that controllers have a clear view of departing aircraft and their surroundings. This allows them to make informed decisions regarding the timing and clearance of takeoffs based on the movements of other aircraft and ground vehicles in the vicinity. In conditions where the departure point is obscured, establishing proper communication and situational awareness becomes significantly more challenging, often resulting in procedural delays or alterations.