Section 7 IFR Procedures
7-8
IDU-450 EFIS Software Version 8.0H (Rotorcraft)
1
st
Ed Nov 2018
7.3.
Overview of Procedures and Instrument Approaches
This Genesys Aerosystems EFIS provides 3-D GPS precision and non-
precision instrument approach guidance using a system integral TSO
C146c BETA 3 GPS receiver with GPS and augmented GPS with Satellite
Based Augmentation System (SBAS) commonly referred to as WAAS
(Wide Area Augmentation System).
Use of this GPS receiver provides a level of certified service supporting
RNAV (GPS) approaches to LNAV, LP, LNAV/VNAV, and LPV lines of
minima within system coverage. Some locations close to the edge of the
coverage may have lower availability of vertical guidance.
Approach with vertical guidance (APV) procedures are defined in ICAO
Annex 6 and include approaches such as the LNAV/VNAV procedures
presently being flown with barometric vertical navigation (BARO-VNAV).
These approaches provide vertical guidance but do not meet the more
stringent standards of a precision approach. With the WAAS BETA 3 GPS
receiver and updatable navigation database in this system, these
approaches may be flown using an electronic glidepath, which eliminates
errors introduced by using barometric altimetry.
In addition to LNAV/VNAV procedures, APV takes advantage of the high
accuracy guidance and increased integrity provided by GBS/SBAS. This
SBAS (TEROS/ICAO) generated angular guidance allows use of the same
TERPS approach criteria for ILS approaches. The resulting approach
procedure minima, localizer performance with vertical guidance (LPV),
have a decision altitude as low as 200 feet height above touchdown (EASA
OPS LPV 250 ft.) with visibility minimums as low as ½ mile (providing the
terrain and airport infrastructure and regulations support the lowest minima
criteria.)
Another non-precision GPS/SBAS approach is certified as a localizer
performance (LP) approach where terrain or obstructions prohibit the
certification of the LPV vertically guided approach. This approach takes
advantage of the angular lateral guidance and smaller position errors
(provided by GPS/SBAS) to provide a lateral only procedure similar to an
ILS localizer. LP procedures may provide lower minima than a LNAV
procedure due to the narrower obstacle clearance surface. In the LP
approach, vertical guidance is for information only and is based on SBAS
or BARO information.
The Genesys Aerosystems EFIS guides the pilot through every step of the
approach procedure with Highway in the Sky (HITS) 3-D symbology. The
system defines a desired flight path based upon the active flight plan. The
current position of the aircraft is determined relative to the desired path in
order to determine lateral deviation for display on the GPS/SBAS CDI and
