What is the approximate level-off pressure altitude after drift-down under Operating Conditions D-3?

The approximate level-off pressure altitude after drift-down under Operating Conditions D-3 is identified as 21,600 feet. This altitude is determined based on specific performance and operational criteria established for aircraft in that category during the drift-down procedure.

In the context of aircraft operations, particularly when discussing drift-down procedures, the altitude is primarily influenced by the aircraft's performance characteristics, including its engine configurations and aerodynamic properties. After an engine failure, the aircraft’s descent is calculated to maximize the glide capability and maintain control while ensuring a safe level-off altitude above any obstructions or terrain.

The selected altitude of 21,600 feet aligns with established guidelines that consider safety margins while accommodating the aircraft's weight, configuration, and environmental factors that could affect performance on descent. This calculation is vital in ensuring that the aircraft can safely navigate to a suitable landing area following an in-flight emergency, reflecting adherence to regulatory standards and operational protocols.

Understanding the rationales behind these altitude selections is crucial for effective flight planning and ensures that dispatchers can make informed decisions in various flight scenarios. Thus, recognizing 21,600 feet as the correct response highlights its importance in training dispatchers for real-world operational challenges.