Do you need waas for lnav vnav free#

The Chelton EFIS is one such unit, and mine was driven by the Free Flight 1201 WAAS GPS. It is possible to use a VNAV slope for approaches, but rare to find a unit that has such a system. A Top of Descent (TOD) is created by the unit telling you when to begin a descent. Either way you can choose a slope or a vertical descent speed for that segment that ends in the chosen waypoint. The way to manually create one is to enter an altitude for a waypoint in the flight plan. These are either created automatically, say as step-down legs in an approach or arrival, or manually. You can generally choose either the angle of the slope or a vertical speed.Īs an aside, VNAV slopes are now common in modern GPS navigators, but are typically used during enroute or terminal phases of flight. Points on the slope are created from your lateral GPS position but using computed baro-altitudes according to the chosen slope and distance from the waypoint. The latter slopes are created by computer from any database waypoint and a baro-altitude at that waypoint. Vertical approaches can be constructed two different ways, one with all points on the slope determined by their GPS altitude and the other using baro-VNAV slopes. But it does allow GPS as your primary navigation system, unlike a receiver without any WAAS. A Class 1 WAAS improves your horizontal position error but does not allow vertical approaches since it computes less than five solutions per second (maybe one per second). LPV approaches require a Class 3 WAAS that computes position five times per second. They also create angular courses on LNAV approaches, though not required. While LNAV and LP approaches have no vertical guidance, manufacturers are adding it (+V) to both LP and LNAV approaches. Approaches at Rocky Mountain Metro Airport (KBJC) in Denver with three GPS variants, each with different minimums.įirst, you need to have a WAAS GPS to fly the LPV, while you can fly the LNAV without a WAAS receiver in your GPS.