Definition
A series of predetermined maneuvers, published by the FAA, for the orderly transfer of an aircraft under instrument flight conditions from the beginning of the initial approach to a landing, or to a point from which a landing may be made visually. Each IAP specifies altitudes, headings, navigation aids, fixes, and minimums that the pilot must follow to descend safely through clouds or low visibility toward a specific runway.
Plain English
A step-by-step set of instructions that lets a pilot fly down through clouds or poor visibility and line up safely with a runway, using only the aircraft's instruments.
Context Anchor
Seen on instrument approach charts, in IFR clearances from air traffic control, and during the arrival phase of an instrument flight.
Derivation
From Latin instrumentum (a tool) and Latin approchier (to come near). An instrument approach is literally 'a structured way of coming near the runway using instruments instead of outside visual references.'
Why Pilots Care
They enable safe landings in low visibility by following standardized routes and altitudes that keep the aircraft clear of obstacles.
Intuition Check
Do not assume an instrument approach procedure is just any approach flown while looking at instruments. In this context, it means a published, approved procedure with exact paths, altitudes, and decision points.
Example Sentence 1
With the ceiling reported at 600 feet, the pilot briefed the ILS instrument approach procedure for Runway 27 before beginning the descent.
Example Sentence 2
ATC cleared the flight for the IAP, allowing the aircraft to begin its published descent to the runway.