Which of the following best describes the Minimum Descent Altitude?

The Minimum Descent Altitude (MDA) is defined as the lowest altitude to which an aircraft may descend on a non-precision approach without visual reference to the runway. At or above this altitude, a pilot must have the runway in sight in order to continue the approach and land safely. If the runway is not visible by the time the aircraft reaches the MDA, the pilot is required to execute a missed approach.

This concept is critical for ensuring safety during the approach phase, as it helps prevent controlled flight into terrain by allowing pilots to establish visual contact with the runway prior to landing.

The other responses do not accurately capture the essence of MDA. While Decision Height pertains specifically to Precision Instrument Approaches and indicates a point where a decision must be made to land or go missed, it is not the same as MDA. The mention of the lowest altitude before executing a missed approach does not encompass the requirement for visual contact, which is key to MDA. Finally, the minimum altitude for safe navigation refers to the terrain clearance and obstacle avoidance, which is a broader concept that does not specifically relate to visual approaches.