Definition
The Localizer Performance (LP) lines of minima are the published approach minimums on an RNAV (GPS) instrument approach chart that apply when the aircraft is using WAAS-based lateral guidance with localizer-like precision but without vertical guidance. LP minima provide a Minimum Descent Altitude (MDA) — not a Decision Altitude — and are flown as a non-precision approach with tighter lateral course sensitivity than LNAV.
Plain English
It is the row on a GPS approach chart that tells you how low you can descend when your GPS is giving you very accurate left-right guidance but no up-down guidance. You level off at the listed altitude and look for the runway, just like on a non-precision approach.
Context Anchor
Seen near the bottom of an RNAV (GPS) approach chart, in the minimums box where the chart lists different authorized approach options such as LPV, LNAV/VNAV, LNAV, or LP.
Derivation
‘LP’ stands for Localizer Performance. The name signals that the lateral accuracy matches a traditional ILS localizer, but the absence of ‘V’ (vertical) tells you there is no glidepath — only sideways precision.
Why Pilots Care
LP minima are higher than LPV minima and can be affected by inoperative ground or aircraft components, directly impacting whether an approach is usable in marginal weather.
Intuition Check
“Lines” here means chart rows, not painted lines on a runway. “Minima” does not mean a target to aim for; it means the lowest legally allowed altitude and visibility for that approach option.
Example Sentence 1
Because the LPV minimums were not authorized at our destination tonight, we briefed the LP lines of minima instead.
Example Sentence 2
The approach plate showed LP lines of minima requiring 1,200 feet and one mile visibility for the RNAV runway 27 procedure.