What is the purpose of the Decision Height (DH) in an approach?

The purpose of the Decision Height (DH) in an approach is to determine when to initiate a missed approach. DH is a specific altitude in precision approaches below which the pilot must have visual reference to the runway or approach lights in order to continue the descent and proceed with the landing. If visual contact is not established by this point, the pilot is required to execute a missed approach. This ensures that the aircraft does not descend below a safe altitude without visual confirmation of the runway, thus maintaining safety in the approach phase.

In this context, while confirming visual contact with the runway is essential and is part of the decision-making process during an approach, the DH specifically defines the altitude where a decision must be made about whether to continue the landing or opt for a missed approach. The other options, such as clearing the airspace below the aircraft or maintaining minimum fuel for landing, do not directly relate to the function of the DH in the context of instrument approaches.