Minimum Descent Altitude

Minimum Descent Altitude (MDA) is the lowest altitude, referenced to mean sea level, to which descent is authorized during a non-precision approach (NPA) when the required visual references for the runway have not been established.

• Used with non-precision approaches (VOR, NDB, LNAV, localizer only)
• Unlike Decision Altitude (DA) used in precision approaches, MDA requires a 'dive and drive' or CDFA technique
• Pilot must not descend below MDA unless the required visual references are in sight
• If visual references are not established by the missed approach point, a go-around is mandatory
• MDA values vary by approach type, aircraft category, and airport equipment
• CDFA (Continuous Descent Final Approach) technique treats MDA similarly to a DA — safer and more fuel-efficient