in Europe you also need some paperwork called Safety Of Life
That is circular – it is a Brussels invention. It is BS.
Oz and NZ use GBAS (G=ground)
I wonder if this famous thing relates ?
Ibra wrote:
you can get L/VNAV and LNAV+V with raw GNSS in new navigators like GTN as long as you have plenty of NAVSTAR satellites (no SBAS signal)
That is not correct with respect to L/VNAV as It requires SBAS and adequate VPL to annunciate and to provide vertical guidance.. I have a GTN and it is not approved with the TSO to do what you say with respect to L/VNAV, but LNAV+V (aka Advisory Vertical Guidance) is allowed inside or outside SBAS SV because the MDA is unchanged and almost any vertical path is clear of obstacles when descending from a FAF to MDA on a NPA approach. That is not true for LNAV/VNAV, as the obstacle clearance surface is sloped and not a level plane. It is true that an LNAV/VNAV approach does not require WAAS when outside a SBAS SV, but in that case Baro-VNAV is required. So LNAV/VNAV is not an SBAS approach, but may be flown with an SBAS GPS using SBAS for the vertical guidance.
These quotes from RTCA DO229D (the technical specification for TSO C145/146 SBAS navigators that SBAS is required for vertical navigation on the final approach segment for LNAV/VNAV if the vertical guidance is from the GPS navigator.
1.5.1 SBAS and Barometric Vertical Navigation
Section 2 of this document addresses the use of SBAS vertical position as used on the final approach segment of an LNAV/VNAV or LPV approach procedure. Section 2.2.3.3.4 addresses using GNSS vertical position for advisory guidance on LNAV approach procedures. The use of SBAS vertical position for other operations is not addressed, as a separate barometric altimeter is expected to provide vertical position during en route operations, terminal operations, and LNAV approaches. The altimeter will be independent of the GPS/SBAS equipment and display directly to the pilot. That barometric altitude is used for determination of minimum segment altitudes, minimum descent altitudes and decision heights and is outside the scope of this document.
Optionally, the equipment may use a baro-altimeter input to provide vertical navigation (VNAV) capability in accordance with applicable requirements and advisory material (e.g., FAA Advisory Circular (AC) 20-129 and RTCA/DO-236B). Barometric VNAV is used in all phases of flight, and can be used for vertical guidance on an LNAV/VNAV approach. Barometric VNAV has universal coverage (ie, is not dependent on SBAS coverage), but there may be temperature limitations for use of barometric VNAV on approach. Class 2 or 3 equipment that provides barometric VNAV must address the integration issues of SBAS-vertical and barometric-vertical.
This is included in the LNAV section , similar wording is not provided in the LNAV/VNAV section:
LNAV equipment may provide advisory vertical guidance. Advisory vertical guidance is defined as supplemental guidance where the barometric altimeter remains the pilot’s primary altitude reference. This advisory guidance should use the vertical path and deviations defined in Section 2.2.4. This advisory guidance may be provided even when SBAS corrections or integrity information is not available. This advisory guidance cannot be used to descend below the LNAV MDA or step-down altitudes.
That is not correct with respect to L/VNAV as It requires SBAS and adequate VPL to annunciate and to provide vertical guidance.. I have a GTN and it is not approved with the TSO to do what you say with respect to L/VNAV, but LNAV+V
I stand corrected, I just cross checked that claim, yes there is no L/VNAV with NAVSTAR only in Australia (only LNAV+V using GNSS in new navigators), it seems they have plan by 2028 with some sort of augmentation…
https://www.icao.int/safety/pbn/PBNStatePlans/Australia%20PBN%20plan.pdf
