If you are unable to issue a clearance at the time of request, what should you provide?

Providing an EDC (Estimated Departure Clearance) time when you are unable to issue a clearance at the time of request is crucial for effective communication and operational efficiency. The EDC time helps pilots understand when they can expect to receive their clearance, allowing them to manage their preparation and expectations accordingly. This practice reduces uncertainty and assists in maintaining the flow of air traffic, as pilots can plan their activities while waiting for the necessary clearance.

In this context, the other options, while useful in different scenarios, do not directly address the pilot's immediate need for a clearance. Weather updates, while important, do not inform the pilot of the timeline for their departure clearance. Flight plan details provide operational information but lack the clarity on timing that an EDC offers. Lastly, the expected landing time is relevant for arrival instructions, rather than departure clearance issuance. Thus, providing the EDC time is the most appropriate and relevant response in this situation.