Garmin G950 Pilot’s Guide for the Pilatus PC-6
190-00870-02 Rev. A
16
SYSTEM OVERVIEW
SY
STEM
O
VER
VIEW
FLIGHT
INSTRUMENTS
EIS
AUDIO P
ANEL
& CNS
FLIGHT
MANA
GEMENT
HAZARD
AV
OID
ANCE
AFCS
ADDITIONAL FEA
TURES
APPENDICES
INDEX
• SBAS Selection (
SBAS
Softkey is pressed)
In certain situations, such as when the aircraft is outside or on the fringe of the SBAS coverage area, it may
be desirable to disable EGNOS, MSAS or WAAS (although it is not recommended). When disabled, the SBAS
field in the GPS Status box indicates DISABLED. There may be a small delay for the GPS Status box to be
updated upon EGNOS, MSAS or WAAS enabling/disabling.
Disabling SBAS
1)
Select the GPS Status Page.
2)
If necessary, press the
SBAS
Softkey.
3)
Press the
FMS
Knob to activate the cursor.
4)
Turn either FMS Knob to select ‘EGNOS’ or ‘MSAS’ or ‘WAAS’, as necessary.
5)
Press the
ENT
Key to uncheck the box.
6)
Repeat steps 4 & 5 as necessary, then press the
FMS
Knob to remove the cursor.
Figure 1-12 Enable/Disable SBAS
RAIM PREDICTION
Receiver Autonomous Integrity Monitoring (RAIM) is a GPS receiver function that performs a consistency
check on all tracked satellites. RAIM ensures that the available satellite geometry allows the receiver to
calculate a position within a specified RAIM protection limit (2.0 nautical miles for oceanic and enroute, 1.0
nm for terminal, and 0.3 nm for non-precision approaches). During oceanic, enroute, and terminal phases of
flight, RAIM is available nearly 100% of the time.
The RAIM prediction function also indicates whether RAIM is available at a specified date and time. RAIM
computations predict satellite coverage within ±15 min of the specified arrival date and time. In most cases
performing RAIM prediction is not necessary. However, in some cases, the selected approach may be outside
the SBAS coverage area and it may be necessary to perform a RAIM prediction for the intended approach.
Because of the tighter protection limit on approaches, there may be times when RAIM is not available. The
G950 automatically monitors RAIM and warns with an alert message when it is not available. If RAIM is not
predicted to be available for the final approach course, the approach does not become active, as indicated by
the messages “Approach is not active”. If RAIM is not available when crossing the FAF, the missed approach
procedure must be flown.
