Section 5 Menu Functions and Procedures
5-22
IDU-450 EFIS Software Version 8.0H (Rotorcraft)
Rev A Apr 2019
NOTE:
The pilot may perform RAIM prediction at a designated waypoint. The
screen has various data entry boxes as follows.
1) Designated Waypoint: Prompted to enter an identifier for the
designated waypoint. If there is a single result from the search, the pilot
is advanced to the UTC time entry box. If there is no result from the
search, the pilot is re-prompted to enter an identifier. If there are
multiple results from the search, a selection list with matching
identifiers is presented and, upon selection, the pilot is advanced to the
UTC time entry box.
INFO (L3)
gives access to information for the
highlighted results.
2) UTC Time Entry: Allows entry of the 24-Hour UTC estimated time of
arrival at the designated waypoint.
3) UTC Date Entry: Allows entry of the UTC estimated date of arrival at
the designated waypoint.
4) PRN Mask Entry: Allows the pilot to specify the PRN number of
satellites expected to be unavailable at the destination.
5) EXIT: Allows exit of the RAIM prediction screen at any time.
6) Once a designated waypoint and UTC estimated time of arrival are
entered,
CALC (R2)
appears for the pilot to initiate the RAIM
Prediction. Press
CALC (R2)
to check the UTC estimated time of
arrival and ensure it is within the current almanac (i.e., <3.5 days from
current date and time). If it is, a Predictive FDE Request message
requesting “Detection Availability” with a required HAL of 0.3NM is sent
to the GPS/SBAS receiver. In response, the GPS/SBAS receiver
replies with a sequence of Predictive FDE Response messages. These
messages are parsed and used to fill in the RAIM Prediction result area
at the bottom of the screen. The RAIM Prediction result area shows the
RAIM Prediction results as “OK” or “XX” for ETA ± in 5-minute
increments. Once a prediction is complete,
START OVER (R2)
allows
the pilot to perform another prediction without exiting the RAIM
Prediction screen.