Definition
A standard instrument approach procedure in which an electronic glide slope or vertical guidance signal is provided, allowing the pilot to descend along a precise vertical path to the runway. Examples include the Instrument Landing System (ILS), Precision Approach Radar (PAR), and Ground Based Augmentation System (GBAS) Landing System (GLS).
Plain English
A type of instrument approach that gives the pilot both side-to-side and up-and-down guidance to the runway, so the aircraft can be flown down a precise sloped path all the way to landing.
Context Anchor
Seen on instrument approach charts, in instrument training, and when choosing or briefing an approach before landing in low visibility.
Derivation
‘Precision’ comes from the Latin praecisio, meaning ‘a cutting off’ or ‘exactness.’ In approach terminology it refers to the exactness of the vertical guidance — the aircraft is held on a precisely defined descent path, not just steered toward the runway.
Why Pilots Care
Allows lower landing minimums than non-precision approaches, increasing the chance of completing the flight in marginal visibility.
Intuition Check
Precision does not just mean “very accurate” in a general sense here. In this FAA use, it means the approach provides approved side-to-side guidance and approved vertical descent guidance.
Example Sentence 1
The pilot briefed the ILS as a precision approach procedure, noting the decision altitude and the glide slope intercept point.
Example Sentence 2
Because the airport offered a precision approach procedure, the pilot could continue the descent below the non-precision minimums.