What is needed for point outs on climbing or descending aircraft when a FDB is not sent?

When it comes to point outs for climbing or descending aircraft, particularly in a situation where a Flight Data Block (FDB) is not sent, it's crucial to have a clear communication of the altitude the aircraft is leaving. This information is vital for air traffic controllers to ensure proper separation and safe traffic management. By stating the altitude that the aircraft is departing from, the receiving air traffic controller can effectively assess the situation and make informed decisions regarding traffic coordination and separation standards.

In the context of air traffic control protocols, having the altitude leaving is essential because it allows the controller to track the aircraft's vertical movement and predict its trajectory. Knowing this detail enables controllers to maintain safety and operational efficiency in the airspace.

Other options such as the aircraft's intended destination, flight time estimates, or weather conditions, while they may be useful for various facets of air traffic management, do not directly provide the essential altitude information required for effective point outs regarding altitude changes. Therefore, the statement of altitude leaving is the most critical piece of information needed in this scenario.