missed approach

A missed approach occurs when a pilot abandons an instrument landing and climbs back to a safe altitude before reaching the runway. This happens at or above the decision height (DH) or minimum descent altitude (MDA), the regulatory floor below which descent cannot continue legally unless the runway is in sight and the aircraft is in position to land safely. The pilot executes published missed approach procedures, which are charted routes and altitude restrictions designed to return the aircraft to a holding pattern or navigate it toward another approach or diversion airport.

Missed approaches are not failures, failures of navigation, or system malfunctions. They are routine, trained responses to legitimate circumstances: weather deteriorating below landing minimums, traffic conflicts requiring go-around commands from air traffic control, aircraft system anomalies detected during descent, or visual references not appearing when expected. A well-executed missed approach is a core safety function that prevents controlled flight into terrain or unstabilized landing attempts.

Variants and triggers

Missed approaches vary by approach type and airport design. A pilot conducting an ILS (instrument landing system) approach at DH might encounter cloudbreak at 500 feet but find forward visibility still inadequate. A non-precision approach relying on VOR or NDB navigation will have a published MDA, often several hundred feet higher than DH, where continued descent becomes illegal without runway in sight. Low-visibility procedures at major airports may trigger a missed approach automatically if the aircraft drifts laterally beyond specified tolerances as it descends the final approach course.

Maintenance personnel encounter missed approaches through their consequences. A go-around at or below 500 feet creates transient structural and aerodynamic loads different from cruise or climb. Landing gear, flaps, and slats cycle rapidly. Engine power increases sharply. Airframe fatigue accumulation depends on how often an aircraft executes missed approaches and at what altitudes they occur. Airlines track missed approach frequency per aircraft as one indicator of operational performance and potential maintenance trends.

The regulatory distinction between DH and MDA reflects approach methodology. Precision approaches using ILS guidance can descend lower (DH typically 200 feet or less above ground level) because the pilot has electronic guidance to the runway threshold. Non-precision approaches without lateral guidance require a higher MDA (often 500 feet to 1,000 feet above ground) to allow time to acquire visual references and maneuver safely. Published missed approach procedures specify climb gradient, turn directions, and altitude targets to integrate with airspace and obstacle clearance requirements.

The term 'missed approach' itself is neutral in origin: it describes an approach that was not completed, not one that failed. The procedure itself, however, is one of the most practiced and safety-critical elements of instrument flying. Pilots train missed approach execution regularly because the ability to go around decisively, without hesitation or fixation on landing, is a fundamental protection against accidents.