Part 4 - Autoslew and SYNC

Welcome to Part-IV of our monthly series on the SN3308 ColorMap HSI. This time we’ll look at the auto-slew and sync features and show how they can reduce your workload during flight, giving you more time to size up the big picture and stay ahead of the aircraft. The SN3308 brings these advanced features into the cockpit of GA aircraft for the first time.

The auto-slew feature will automatically rotate the course pointer to the desired course being sent from your GPS while it is in normal LEG or SEQ mode. This eliminates the need to manually rotate the course pointer knob at each waypoint on your GPS flight plan - also eliminating the MSG annunciation telling you to do so. With your autopilot in NAV mode, the SN3308 will fly your flight plan ‘hands-off’, freeing you to concentrate on other duties during flight.

In the screen shot at right we’re leaving the Portland, Oregon Class C airspace northbound on V 23 approaching the Battle Ground VOR (BTG). Distinct colors are used for easy interpretation of the data. Notice that the active flight plan leg is shown in magenta, the upcoming leg in white and the course pointer in cyan. The green dashed lines depict Class C airspace. To stay on the airway after BTG the display shows a twenty-degree left turn at the station, and the GPS "WPT" annunciator flashes on the screen, giving a clear indication of the approaching waypoint. With auto-slew enabled, the course pointer will then turn automatically causing the autopilot to fly the new course. Try that with a mechanical HSI!

IFR Enroute on V 23 near UBG VOR after pressing SHFT>SYNC

NAV: NAV1	MAP: ON
BRG1: NAV1	BRG2: OFF
VUE: 360	RANGE: 30nm
COURSE POINTER: ON

IFR Enroute on V 23 north of Portland, approaching the BTG VOR

NAV: GPS1	MAP: ON
BRG1: GPS1	BRG2: OFF
VUE: ARC	RANGE: 5nm
COURSE POINTER: ON

Let’s consider another example which uses the SYNC button to perform a very useful function: centering the CDI needle and navigating direct-to a VOR.

In the screen shot at left we’re approaching Portland from the south on V 23. We’re told to proceed direct to the Newburg VOR (UBG), a 60-degree left turn, as a temporary vector for traffic. By pressing the NAV button on the SN3308, we can change the NAV source from GPS to our NAV1 radio. Notice that the course pointer and NAV information are now in green. The magenta line indicates the original flight plan along V 23. The SN3308’s course-sync function makes navigation to the off-course VOR a snap: after tuning UBG on the NAV receiver, press SHFT and then SYNC to automatically center the CDI needle and rotate the course pointer until it is pointing at the VOR as shown. Keep the needle centered and we’re tracking directly to the VOR until ATC allows us to return to our original course.

Did you know that no EFIS system – at any price – has the features of the SN3308? Our solution now allows you to install EFIS capability into your aircraft at a fraction of the cost of obsolete CRT technology.

Now that you’ve had a glimpse of the SN3308 capabilities in the enroute phase, in part-V we’ll explore approach scenarios.

Next: Part 5: The ILS Approach.

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