Minimum distance separation can be applied between two departing Category III aircraft if distances can be determined by reference to suitable landmarks, provided that the preceding aircraft is ___.

• A. airborne
• B. on the ground
• C. in the climb
• D. taxiing

Answer: (A)

Minimum distance separation that uses landmarks relies on measuring how far apart two aircraft are while the lead is already in the air. The reason is that landmarks give a fixed reference to determine air distance, and only when the preceding aircraft is airborne does that measurement reflect the actual separation in the airspace as the second aircraft follows on the departure path. If the lead is still on the ground, the distance to those landmarks wouldn’t accurately represent their positions in the air, and the trailing aircraft could close the gap unpredictably as the lead lifts off.

So, this method is valid when the preceding aircraft is airborne.