Definition
The lowest altitude and visibility values authorized for a precision instrument approach — that is, an approach that provides both lateral (left/right) and vertical (up/down) electronic guidance to the runway, such as an ILS. Precision minimums are published as a Decision Altitude (DA) or Decision Height (DH) and a required visibility, below which the pilot must execute a missed approach if the runway environment is not in sight.
Plain English
The lowest height you can descend to, and the least visibility you can have, on an approach that gives you both side-to-side and up-and-down guidance. If you reach that height and still can't see the runway, you have to go around.
Context Anchor
Seen on instrument approach charts and in side-step maneuver discussions, especially when comparing the lower minimums for the runway served by the precision approach with the usually higher side-step minimums for a nearby parallel runway.
Derivation
Precision' here refers to the approach providing precise vertical guidance, not to the minimums themselves being more exact. The contrast is with 'non-precision' approaches, which give only lateral guidance.
Why Pilots Care
They determine whether a landing can be completed or a missed approach must be flown, directly affecting safety and go/no-go decisions.
Intuition Check
Precision minimums do not mean “the pilot must fly precisely.” They mean the published lowest altitude and visibility limits for a precision approach.
Example Sentence 1
Because the ILS was in service, the crew briefed the precision minimums of 200 feet DA and 1/2 mile visibility.
Example Sentence 2
Review the approach chart to verify the precision minimums before starting the final approach segment.