System overview, Raim prediction – Garmin G950 Tecnam 2006T User Manual

Page 27

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190-01146-00 Rev. A

Garmin G950 Pilot’s Guide for the Tecnam P2006T

15

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

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 WAAS 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.

Predicting RAIM availability:

1)

Select the GPS Status Page.

2)

Press the RAIM Softkey.

3)

Press the FMS Knob. The ‘WAYPOINT’ field is highlighted.

4)

Turn the small FMS Knob to display the Waypoint Information Window.

5)

Enter the desired waypoint:

a)

Use the FMS Knob to enter the desired waypoint by identifier, facility, or city name and press the ENT Key. Refer
to Section 1.7 for instructions on entering alphanumeric data into the G950.

Or

:

a)

Turn the small FMS Knob counter-clockwise to display a list of flight plan waypoints (the FPL list is populated
only when navigating a flight plan).

b)

Turn the small FMS Knob clockwise to display the NRST, RECENT, or AIRWAY waypoints, if required.

c)

Turn the large FMS Knob clockwise to select the desired waypoint. The G950 automatically fills in the identifier,
facility, and city fields with the information for the selected waypoint.

d)

Press the ENT Key to accept the waypoint entry.

6)

Enter an arrival time and press the ENT Key.

7)

Enter an arrival date and press the ENT Key.

8)

With the cursor highlighting ‘COMPUTE RAIM?’, press the ENT Key. Once RAIM availability is computed, one
of the following is displayed:

• ‘COMPUTE RAIM?’—RAIM has not been computed for the current waypoint, time, and date combination

• ‘COMPUTING AVAILABILITY’—RAIM calculation in progress

• ‘RAIM AVAILABLE’—RAIM is predicted to be available for the specified waypoint, time, and date

• ‘RAIM NOT AVAILABLE’—RAIM is predicted to be unavailable for the specified waypoint, time, and date

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