instrumentlandning

Instrumentlandning, or instrument landing, is a set of aviation procedures that enable a safe landing in reduced visibility using instrument flight rules and ground-based navigation aids. The approach relies on cockpit instruments and air traffic control guidance rather than visual cues.

The principal system is the Instrument Landing System (ILS), which provides lateral guidance from a localizer and vertical guidance from a glide slope. Other precision approaches have emerged, including satellite-based GLS and GNSS-based APV methods such as LPV. Non-precision approaches use navigation aids like VOR or NDB, sometimes with RNAV-derived guidance. Approaches with vertical guidance (APV) offer advisory vertical guidance but do not meet the ICAO definition of a precision approach; they require pilots to fly step-down or continuous descent profiles. Minima vary by equipment and category.

Operation: Instrument landings require pilot qualifications (IFR), aircraft equipment suited to the approach, and an ATC clearance. The runway’s lighting and approach aids must be calibrated, and the crew may rely on autopilot coupled to the ILS or other system to fly the approach. Minima specify decision heights or minimum descent altitudes and visibility requirements. Cat I, II, and III classifications describe capability for very low visibility landings, with progressively lower minima.

History: Instrument landing procedures developed in the mid-20th century with the deployment of ILS and related technologies, becoming standard for commercial aviation. Modern developments continue with GNSS-based approaches and improved airport illumination and guidance systems.