WAAS

[brien23]

Instrument RNAV (GPS) approach procedure charts the upper left corner procedure notes when it lists WAAS and the minimums block lists LNAV MDA non percision approach does the GPS that you use have to be WAAS compliant or can you use a older IFR GPS not WAAS compliant?

 

[mantakos]

Many approaches have both LPV minimums and LNAV minimums, and a little box that gives a WAAS channel number and approach ID.

Such approaches can be flown with a C146 (i.e. waas-capable) IFR-approved GPS using the vertical guidance and the LPV minimums, and with a regular old C129 (i.e. pre-waas) IFR-approved GPS using "dive and drive" step-downs and the LNAV MDA.

You can think of the approach plate as being shared for the two approach types.
-harry

 

[poadeleted20]

Note that there are a few RNAV(GPS) approaches out there designed for WAAS use only, but the lack of LNAV-only minima is a good hint about that. As long as there are LNAV-only minima, you can fly it with a c129 GPS to those LNAV-only minima.

 

[John Collins]

Instrument RNAV (GPS) approach procedure charts the upper left corner procedure notes when it lists WAAS and the minimums block lists LNAV MDA non percision approach does the GPS that you use have to be WAAS compliant or can you use a older IFR GPS not WAAS compliant?

All the WAAS Channel number is for is to provide an alternative method of selecting the RNAV approach without having to enter the airport identifier. This feature is not used often but comes in handy when you are conducting practice approaches at different nearby airports.