Plain English Meaning

The lowest altitude you are allowed to descend to on a GPS approach when your equipment is giving you both side-to-side and up-and-down guidance down to the runway. Because you are flying a steady descent path rather than stepping down, this minimum is shown as a Decision Altitude — the point where you must either see the runway or go around.

Full Definition

The published minimum descent values on an RNAV (GPS) approach chart that apply when the aircraft is using both lateral (LNAV) and vertical (VNAV) guidance from approved navigation equipment. These minimums consist of a Decision Altitude (DA) rather than a Minimum Descent Altitude (MDA), because the approach is flown along a continuous, computed . To use LNAV/VNAV minimums, the aircraft must have an approved capable of providing the , such as or a system, and any , equipment, or on the chart must be observed.