Is there any airport which has a precision instrument approach using only GNSS (augmented with LAAS) for guidance?

  • $\begingroup$ Are RNP approaches precision? $\endgroup$ – Steve Kuo Jan 31 '18 at 22:21

The FAA has an FAQ on GBAS (ground-based augmentation of GPS/GNSS). It says they no longer use the term LAAS, instead they now use GBAS to be consistent with ICAO terminology. A GBAS approach is called GLS on the approach charts.

The FAQ has information about where GBAS is used:

Where are operational GBAS systems located?

Currently, two U.S. locations have obtained operational approval for public GBAS use and support revenue airline traffic. These stations are located at Newark Liberty International Airport (EWR) and Houston George Bush Intercontinental Airport (IAH). Internationally, several airports have GBAS and support revenue operations (Bremen and Frankfurt, Germany; Sydney, Australia; Malaga, Spain; Zurich, Switzerland; and 15 Russian locations).

Newark (KEWR) has 5 GLS approaches, Houston (KIAH) has 6. I looked at a couple of the approach plates and they didn't require any additional equipment apart from the GBAS equipment itself. Note that GBAS is not the same as the 'typical' GPS/WAAS combination used for RNAV GPS approaches, and it requires different equipment:

Can the same avionics be used for GBAS and WAAS?

The GBAS and WAAS standards are different and initial avionics and integrations only supported one of the two capabilities. Emerging aircraft integrations can support both services (e.g. A350).

  • $\begingroup$ you wrote "Note that GBAS is not the same as the typical GPS/WAAS combination used for RNAV GPS approaches " ; I am a bit confuse, GPS/WAAS cannot be used for precision approaches right? RNAV approaches using GPS MUST be GBAS to be considered precision approaches, am I right? $\endgroup$ – Andrea Ghilardi Feb 1 '18 at 8:22
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    $\begingroup$ @Ghilardi It depends what you mean by "precision". See this answer but it looks like ICAO has a somewhat confusing definition that doesn't include LPV. However, at least in my GA experience, most pilots use "precision" to mean simply "with vertical guidance", which does include LPV. $\endgroup$ – Pondlife Feb 1 '18 at 19:41
  • $\begingroup$ yes, I have read it and unfortunately still confuse anyway. I will dig deeper in that. Thank's @Pondlife $\endgroup$ – Andrea Ghilardi Feb 2 '18 at 7:33
  • $\begingroup$ According to the current FAA/ICAO definitions, GLS (i.e. with GBAS) precision approaches are completely separate from RNAV (with or without SBAS) non-precision approaches. In practice, ILS Cat II/III is a completely different beast from ILS Cat I, and the split between GLS and RNAV looks like it'll be similar if not worse. $\endgroup$ – StephenS Jan 30 '19 at 4:21

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