What are minimum descent altitudes?

Minimum descent altitudes (MDAs) are critical altitudes defined during instrument approaches. This altitude represents the lowest point to which an aircraft can descend on a given approach procedure without requiring visual reference to the runway or landing area. When operating under instrument flight rules (IFR), pilots must adhere to MDAs when conducting approaches in reduced visibility conditions.

Descending below this altitude without the necessary visual cues can compromise safety by increasing the risk of obstacles or terrain collisions. Therefore, compliance with the MDA is essential for ensuring a safe approach and landing in IFR conditions.

Other options misinterpret the purpose of MDAs. For instance, the operational requirements for landing gear deployment and the altitude for visual navigation are not specified by MDAs, and the altitude meant to avoid obstacles incorporates different parameters and considerations.