Definition
A non-precision WAAS-based instrument approach line of minima that provides lateral guidance with accuracy comparable to a localizer, but without vertical guidance. LP minima are published on RNAV (GPS) approach charts and require WAAS-capable avionics. Because LP has no glidepath, the pilot descends to a Minimum Descent Altitude (MDA) rather than flying to a Decision Altitude (DA).
Plain English
LP is a type of GPS approach where the satellite-based system gives you tight left-right guidance to the runway, but you still have to step the airplane down to a minimum altitude on your own — there is no electronic glide path to follow.
Context Anchor
Seen on RNAV (GPS) approach charts, especially in the minimums section, and sometimes displayed by the GPS as the active approach guidance mode.
Derivation
Localizer Performance: 'localizer' is the lateral-guidance component of an ILS, and 'performance' here means the WAAS signal delivers lateral accuracy similar to that localizer — even though no actual localizer transmitter is involved.
Why Pilots Care
It supplies lower landing minimums than basic GPS approaches when vertical guidance is unavailable.
Intuition Check
LP does not mean the same thing as LPV with the V removed. LP is lateral guidance only; LPV includes approved vertical guidance.
Example Sentence 1
WAAS was working normally, so the crew briefed the LP minima for the RNAV (GPS) approach into the smaller airport.
Example Sentence 2
With the WAAS receiver operating, the aircraft reached LP minimums and the runway was in sight.