What defines a low close-in obstacle?

A low close-in obstacle is defined as one that requires a specific terrain clearance during the initial phase of flight after takeoff, particularly in relation to the Departure End of the Runway (DER). This definition involves the requirement for a climb gradient that exceeds 200 feet per nautical mile until the aircraft reaches an altitude of 200 feet above the DER. This is critically important in flight planning because such obstacles could significantly impact safety and performance during takeoff.

Understanding the implications of a low close-in obstacle necessitates considering its impact on climb performance; any challenge to maintaining the necessary gradient directly relates to the potential for collision with the obstacle. Recognizing and appropriately classifying obstacles in this manner ensures that pilots can adequately prepare and adjust their flight operations to maintain safety margins.