What condition prevents you from forwarding departure time or subsequent strip posting time?

The correct answer highlights a specific condition related to the timing of departure in air traffic control operations. When the assumed departure time is within three minutes of the actual departure time, reality dictates that the controller should not forward that information. This is because the proximity of the assumed departure time to the actual time may cause discrepancies or confusion in coordination with other facilities or controllers. It is crucial for controllers to have accurate and timely information to maintain safety and efficiency in the airspace.

In this context, if the assumed and actual times are too close, it limits the ability to update flight progress effectively, which is vital in managing air traffic and ensuring that all involved parties have the most current data. This helps prevent potential conflicts or misunderstandings regarding the aircraft's status.

Other conditions, such as delays, busy traffic periods, or when a receiving facility is closed, do affect operations but are not as directly linked to the specified timeframe that requires precise coordination. Hence, they would not specifically prevent forwarding departure times in the same manner.