The LPV Converter was developed for all Cessna Citation Jets which are either equipped with the legacy Honeywell SPZ5000 System or with Proline21 without the capability to display glideslope information on the Electronic Flight Instrument System (EFIS) (EHSI/PFD) and consequently where LPV approaches are not possible.
This unit is designed to allow for GPS based vertical approaches using the aircraft's preinstalled EFIS system when it is operated in the NAV/ILS mode.
The LPV-Converter resolves the arising problem with the LPV/VNAV-approach that appears, when an aircraft is equipped with an EFIS system (e.g. Honeywell SPZ5000 in Cessna 525 or Thales system in EC135/145) and a SBAS capable (WAAS/EGNOS) FMS/GPS with an ARINC429 interface.
In ILS mode, the EFIS system expects ARINC429 localizer deviation, glideslope deviation and ILS energize information. If a LPV/VNAV approach is active, the LPV/VNAV-Converter switches the ARINC GPS output from the Garmin unit into the NAV input of the EFIS system. The LPV/VNAV Converter extracts ARINC429 data and the DME compliant data from any SBAS capable FMS/GPS datastream and fits additional labels into the generated modified datastream to the EFIS system.
Due to the missing glideslope feature of the EFIS, the LPV/VNAV –Converter simulates an approach signal like an ILS (LOC/GS) to drive the autopilot during a GPS approach with LNAV/LPV capability. While the ILS mode is active, the EFIS system expects ARINC429 labels (localizer deviation, glideslope deviation and ILS energizer information). In case of a SBAS (LNAV/LPV) capable GPS approach will be executed, the “Approach Active Discrete” enables the LPV/VNAV-Converter to supply the EFIS system AP-NAV-Input with ILS comparable GPS approach data. At the same time, the LPV/VNAV -Converter switches the DME information into GPS distance, speed and time information, shown on the EFIS display.