Definition
An instrument approach procedure that provides electronic guidance in both the lateral (left/right) and vertical (up/down) dimensions, meeting ICAO Annex 10 standards for precision. Examples include the Instrument Landing System (ILS), Precision Approach Radar (PAR), and the GBAS Landing System (GLS).
Plain English
An instrument approach that gives the pilot guidance for both staying on the correct path side-to-side and descending at the right angle to the runway.
Context Anchor
Seen on instrument approach charts and in final approach segment discussions, especially when identifying what kind of guidance the approach provides near the runway.
Derivation
"Precision" comes from the Latin praecisio, meaning "a cutting off" or "exactness." In this context it refers to the exactness of the vertical guidance — the approach precisely defines the descent path to the runway, not just the lateral track.
Why Pilots Care
Provides the vertical guidance needed to descend safely in low visibility, lowering the chance of controlled flight into terrain.
Intuition Check
Do not read precision approach as just any approach flown carefully. In FAA use, it means a specific kind of instrument approach that provides approved sideways and downward guidance to the runway.
Example Sentence 1
The ILS to Runway 27 is a precision approach, so we can fly it down to a 200-foot decision height.
Example Sentence 2
Precision approaches are preferred in low ceilings because they provide a glide path the pilot can follow all the way to the runway.