Originally Posted by
pilot dude
Not knowing how your airplane works on most of the airplanes I’ve flown you have to download the approach from the database. As soon as you download a LNAV/VNAV approach it will load this approach and will use a BARO calculated VNAV path and not an SBAS glide path. It will use a more accurate GPS position for determining the position of your plane but the VNAV path and the SBAS path are two entirely different path systems. with the BARO VNAV the GS beam is straight and a dot deviation at 6 miles will be the same as a dot deviation at 0,5 NM from the runway. The LPV glide path will get more sensitive as it gets closer to the runway. In short, UK doesn’t have LPV capability and an LNAV/VNAV approach is not the same as an LPV approach.
Ah fair point. My system is only certified for the LNAV/VNAV SBAS not LNAV/VNAV Baro. The LNAV/VNAV SBAS approach is a combo of an LNAV (linear) and a VNAV SBAS (angular). But the Garmin 750 we have actually flies LNAV as angular (go figure). This means the indications for an LPV (angular lateral and vertical) are identical to the LNAV/VNAV SBAS (angular lateral and vertical on a Garmin). Hence practically in my installation LPv and LNAV/VNAV are the same.