Sorry if this has been asked before, but say you have an RNAV approach plate specifying LPV minimums, and also LNAV/VNAV minimums.When flying it with the NGX in IAN mode, which minimums should I use ?Thank you

LPV minima require a TSO C145a/C146a WAAS capable receiver. While I'm fairly certain that WAAS is an option that Boeing provides for the NG, I doubt that it is used since it will require additional flight crew training to fly these approaches, something that the airlines loath to do. LPV uses the WAAS augmented increased GPS accuracy to obain final approach course guidance that is the equal to an ILS localizer. Therefore, the minimums are same or nearly so for an ILS and a LPV approach, assuming that the runway has necessary approach lighting system, markings, etc to support an ILS approach. LNAV/VNAV minima is based on the accuracy TSO C129a approach capable GPS. This is what is normally equipped on the Boeing aircraft that has GPS installed as part of the FMC sensor suite. The final approch guidance is linear, which result in more obstcles being picked up within the proctected airspace as the aircraft descends towards the runway. Therefore, the LNAV/VNAV minima will be higher than the LPV minma.For the NGX, you should use the LNAV/VNAV line of minima.Hope that this helps!Rich Boll

Thanks !