When is an ODP (Obstacle Departure Procedure) required?

An Obstacle Departure Procedure (ODP) is specifically designed to provide a safe departure route for an aircraft when there are obstacles in the vicinity of the departure airport. The requirement for an ODP is particularly relevant when an obstacle penetrates the 40:1 obstacle identification surface. This surface serves as a protective barrier, ensuring that departing aircraft have sufficient clearance from obstacles during the initial climb phase.

If an obstacle is identified within this surface, an ODP helps pilots navigate safely by outlining a specified departure route that mitigates the risk of collision with such obstacles. This is crucial in maintaining safety, particularly in complex environments where visual references may not be clear or available.

The other options, while they pertain to specific flight scenarios and regulations, do not directly define the circumstances under which an ODP is required. The presence of obstacles that encroach upon the designated clearance surface highlights the need for prescribed procedures to ensure a safe ascent and avoid potential hazards during departure.