Definition
A runway equipped with an electronic glide slope and localizer (such as an Instrument Landing System) that provides pilots with both lateral and vertical guidance for an approach to landing in low-visibility conditions. Precision instrument runways are supported by specific approach light systems and runway markings designed to meet the lower visibility minimums permitted by precision approach procedures.
Plain English
A runway set up with electronic equipment that guides the pilot down a sloped path to the touchdown point, not just left and right but also up and down, so it can be used safely when visibility is poor.
Context Anchor
Seen in airport lighting, runway marking, and approach light system discussions, especially when comparing visual, nonprecision instrument, and precision instrument runways.
Derivation
‘Precision’ comes from the Latin praecisio, meaning ‘a cutting off’ or ‘exactness.’ In this context it signals that the approach guidance is exact in both directions — lateral and vertical — rather than just lateral, as on a non-precision runway.
Why Pilots Care
Determines the lowest weather minimums a pilot is allowed to use for landing and affects approach briefing and equipment requirements.
Intuition Check
Precision instrument runway does not mean the runway itself is built more perfectly than other runways. It means the runway is served by an approved approach that gives the pilot precise side-to-side and descent-path guidance.
Example Sentence 1
The approach chart showed Runway 27 as a precision instrument runway, so we briefed the ILS approach with its lower minimums.
Example Sentence 2
Runway 27L is a precision instrument runway, so the pilot planned for a decision height of 200 feet.