Definition
An instrument approach procedure that provides lateral course guidance to a runway or airport but does not provide vertical (glidepath) guidance certified to precision standards. The pilot descends in steps to a published minimum descent altitude (MDA) and must visually acquire the runway environment before descending below it.
Plain English
A type of instrument approach where the equipment tells the pilot which direction to fly to line up with the runway, but does not give a precise up-and-down path to follow. The pilot descends to a fixed minimum altitude and then has to see the runway to land.
Context Anchor
Seen on instrument approach charts and in instrument training, especially when discussing the transition from flying by instruments to landing by outside visual cues.
Derivation
Nonprecision' simply means 'not precision.' A precision approach (like an ILS) provides certified vertical guidance; removing that vertical guidance is what makes an approach 'nonprecision.' The label describes what the approach lacks, not how carefully it must be flown.
Why Pilots Care
These approaches demand careful altitude management because there is no electronic glideslope, making pilots more susceptible to misjudging height when optical illusions are present.
Grounding Statement
On this kind of approach, the instruments can help you stay lined up, but they may not tell you exactly how steeply to descend.
Intuition Check
Nonprecision does not mean sloppy, unsafe, or less professional. It means the approach lacks precise electronic vertical guidance, so the pilot must manage the descent using the published procedure and safe visual judgment.
Example Sentence 1
Because the airport had no ILS, the crew briefed the VOR approach as a nonprecision instrument approach and planned a step-down descent to the MDA.
Example Sentence 2
On the nonprecision instrument approach the crew maintained a constant airspeed while descending in steps to avoid descending below the safe altitude too early.