Definition
Ground-based and satellite-based navigation systems that guide an aircraft from the en route environment down to a point near the runway from which a landing can be made under instrument flight rules. These systems include precision approaches such as the Instrument Landing System (ILS), nonprecision approaches such as VOR, NDB, and LOC, and performance-based approaches using GPS and WAAS, each defined by published procedures with specified courses, altitudes, and minimums.
Plain English
The collection of equipment and procedures that lets a pilot fly down to a runway safely when they cannot see the ground because of clouds or low visibility. Each system gives the pilot directional and sometimes vertical guidance until they are close enough to land.
Context Anchor
Seen when studying instrument approaches, approach charts, and the equipment used to guide an aircraft toward landing in low visibility or cloud.
Derivation
Instrument refers to flying by reference to cockpit instruments rather than outside visual cues. Approach means the segment of flight where the aircraft transitions from en route navigation to landing. Together the term describes the systems that make a guided arrival possible without seeing the runway until the final moments.
Why Pilots Care
These systems make landings possible in weather that would otherwise force a diversion or missed approach, directly improving safety and schedule reliability.
Intuition Check
Do not read “instrument approach” as simply “using the cockpit instruments while approaching.” Here it means a specific approved method, supported by navigation equipment and a published procedure, for getting to a runway when outside visual cues are limited.
Example Sentence 1
Before the flight, she reviewed the instrument approach systems available at her destination and chose the ILS because the ceiling was forecast to be low.
Example Sentence 2
During preflight planning the crew studied the instrument approach systems available at the destination to choose the best option for the reported ceiling.