12/12/2023 0 Comments Lnav vnav vs lpvFrom the Pilot/Controller Glossary:ĪREA NAVIGATION (RNAV)-A method of navigation which permits aircraft operation on any desired flight path within the coverage of ground− or space−based navigation aids or within the limits of the capability of self-contained aids, or a combination of these. This is like saying, “I don’t care if you use Google maps, Apple maps or Mapquest, as long as you make it to the destination.” The problem arises with what to call this when performance is what matters and all we’ve used in the past is device-specific nomenclature.Įnter area navigation (RNAV). If you had an approved navigation device that met the performance requirements, regulators wouldn’t dictate what system to use. The idea behind PBN is simple: equipment used doesn’t matter performance does. The FAA has been articulating a performance-based navigation (PBN) strategy since 2003. These are generally referred to as global navigation satellite systems (GNSS). There are other satellite-based navigation systems such as GLONASS, Galileo and Beidou, and Garmin already makes devices that receive signals from multiple constellations. Peering into the future, GPS is too limited a moniker. The result is the term “GPS” that is now associated with multiple MOPS. GPS itself (TSO-Ĭ129) as a supplemental navigation system wasn’t good enough for approaches, so approvals as a normal navigation system (TSO-C145), incorporation of SBAS and selective availability awareness were added. It also means the localizer and glideslope receivers meet the minimum operational performance standards, or MOPS, of TSO-C36e and TSO-34e, respectively.Īll was fine until aviation got too smart for its own good. For example, an ILS approach means the localizer is transmitted on a VHF frequency and glideslope on a paired UHF frequency. Thus, a system used for an approach incorporated two aspects, how navigation information was received (the box) and the required performance of the system. ILS, VOR, NDB, GPS, etc.Įach individual system performed to a common standard. Approaches were designated based on the system used for lateral guidance in the final approach segment, e.g. We don’t make these up we just explain them.) When area navigation was first used for approaches, a standard and straight-forward naming convention already existed. The controversy surrounds defining RNAV/RNP and what those terms mean to pilots. ICAO wants to re-name RNAV approaches RNP and the FAA is balking at the idea-as are many other countries. The meanings that words convey are particularly important in aviation and are the genesis of a food-fight between ICAO and the FAA. But this is an over-simplification because changing the subject would make the quote non-sense: That which we call a fish by any other name would smell as sweet. The most trusty is still the ILS if you want vertical guidance.Shakespeare elegantly downplays the importance of naming in Romeo and Juliet, writing: “What’s in a name? That which we call a rose by any other name would smell as sweet.” What matters is the subject and not what the subject is called. Unfortunately the Garmins don’t show that info like they would in the real thing. LPV vs LNAV/VNAV vs LNAV based on its current abilities. How it should work is that your avionics tell you which approach it’s using, e.g. Look up the approach plate via the FAA if you’re flying the US and check the bottom to see which types of RNAV approaches are actually available. If it happens to be an LPV approach, sometimes you’ll get a proper glidepath but it’s pretty random in my experience. Some other variations of RNAV approaches are the WAAS LP (localizer performance, which is precise lateral guidance only), GPS LNAV (lateral navigation only but less precise), LNAV/VNAV (lateral guidance with vertical navigation VNAV mostly does not work in MSFS except for in some mods).Īnyway, basically YMMV right now with RNAV approaches. Sometimes I don’t get guidance until 1 mile out, like describes. Though, these are very hit-or-miss in MSFS right now. It gives you a glidepath like an ILS would, though technically it’s not a “precision” approach it will also get you down to 200 AGL usually. The ILS-like WAAS approach in the US is called LPV (localizer performance with vertical guidance). There are different variations of RNAV approaches, just like there are variations in radio-based approaches (VOR vs LOC vs ILS).
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