During approach, if the radio altimeter indicates 950 ft, what does this measurement refer to?

The measurement indicated by the radio altimeter at 950 ft refers to the height of the lowest wheels of the aircraft relative to the ground. Radio altimeters use radio waves to determine the distance between the aircraft and the ground directly below it, which provides an accurate height measurement that is particularly useful during landing and approach phases. This information is crucial for pilots to ensure safe clearance above the terrain and to manage their approach accurately.

In the context of flight operations, it is vital to understand that this measurement is specific to the aircraft's lowest point concerning the terrain directly below it, making it essential for understanding the aircraft’s position in the approach phase and helps in avoiding obstacles and ensuring that the landing can be conducted safely.