GNSS/RNAV Approaches in Canada: LPV, LNAV, and What the INRAT Tests

GPS approaches have replaced VOR approaches at most Canadian airports, and the INRAT reflects that. But candidates constantly mix up LPV, LNAV/VNAV, and LNAV — three different approach types with different minimums, different equipment requirements, and different rules. Here's how to keep them straight.

The three GNSS approach types in Canada

NavCanada publishes GNSS/RNAV approach plates for airports across the country. On any given plate you might see up to three sets of minimums — one for each approach type. The type you can fly depends on your aircraft's avionics.

LPV: the one that acts like an ILS

LPV approaches require an SBAS-capable GPS receiver (in Canada, WAAS is the SBAS system). The approach provides both lateral and vertical guidance, with minimums expressed as a Decision Height — the same concept as an ILS. When you reach the DH, you either have the required visual references or you go missed.

This is the key exam point: LPV is not classified as a precision approach under ICAO or Transport Canada definitions, even though it behaves like one. The official category is APV (Approach with Vertical guidance). The INRAT will test this. Don't say LPV is precision — it isn't, technically.

LNAV/VNAV: vertical guidance without SBAS

LNAV/VNAV provides an advisory vertical glidepath using barometric VNAV (Baro-VNAV) rather than SBAS. This means your altimeter setting must be correct and the temperature limitations on the approach plate must be respected — Baro-VNAV becomes inaccurate in very cold temperatures.

Minimums for LNAV/VNAV are expressed as a Decision Altitude (DA), not a Decision Height. DA is referenced to mean sea level; DH is referenced to threshold elevation. On the INRAT, the distinction between DA and DH matters. DA = MSL reference, DH = AGL reference above touchdown.

LNAV: lateral only, MDA applies

LNAV gives you GPS lateral guidance to the runway but no vertical guidance at all. You descend to the Minimum Descent Altitude and level off, then look for the runway. This is a traditional non-precision approach structure — the same concept as a VOR or NDB approach.

Standard GPS receivers (non-SBAS) can fly LNAV approaches. If your GPS isn't WAAS-capable, LNAV is your GPS minimum. You also need to verify RAIM availability before the approach — GPS integrity monitoring that confirms the position solution is reliable enough for the approach.

RAIM vs SBAS: what you need to know

RAIM (Receiver Autonomous Integrity Monitoring) is a self-checking function inside your GPS. For LNAV approaches without SBAS, you need to confirm RAIM availability for the approach — this is done during preflight using a RAIM prediction tool or by checking NOTAMs.

With SBAS (WAAS), the ground network continuously monitors satellite integrity and sends corrections. SBAS replaces the need for RAIM prediction because the system monitors itself externally. If your GPS is WAAS-capable and WAAS is available, you can fly LPV or LNAV/VNAV without a separate RAIM check.

What the INRAT actually tests

The exam focuses on three things when it comes to GNSS approaches:

1. Approach type identification — given an approach plate excerpt, identify whether the minimums shown are DH (LPV), DA (LNAV/VNAV), or MDA (LNAV)
2. Equipment requirements — which approach type requires SBAS/WAAS, which requires Baro-VNAV, which works with basic IFR GPS
3. Precision vs non-precision classification — LPV and LNAV/VNAV are both non-precision (APV). Only ILS and PAR are precision.

Study the TP 691E section on RNAV approaches alongside the ILS approach material — the contrast between how an ILS and LPV are structured, despite their similar minimums, is exactly the kind of thing the exam probes.