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View Full Version : Connecting a 5600 to a GTN650



art.pileggi
07-11-2012, 02:32 PM
When the GTN650 starts up it is supposed to allow me to enter fuel on board and fuel flow. It will then use this information to display range rings.

When my starts up, if the 5600 comes up first the GTN650 will not allow me to enter to information. If the GTN650 comes up first I can enter it, but as soon as the 5600 comes up it forgets what I entered. After reading the GTN650 manual it appears the GTN was incorrectly configured for fuel sensors but the manual does not explain how to change this setting. I called Garmin but they just said to take the unit to an authorized dealer and my Tecnam dealer who installed the system claims they can't change it.

I read the 5600 manual again and I notice it shows a GTN configuration screen for the RS-232 port with the name Fuel Format 1. How do I get to this screen?

Rob Hickman
07-11-2012, 05:26 PM
Art,

Your GTN-650 is connected to the EFIS engine monitor and is getting the fuel flow and the amount of fuel on board from the EFIS. When you add fuel to your aircraft you should always update the EFIS Engine monitor totalizer and it will then send the correct data to your GTN-650. The entering fuel on the GTN startup screen is for the unfortunate people that don’t have a fuel totalizer in the plane that can talk to the GTN.

Entering a single value for the fuel burn does not make a lot of sense. In my RV-10 I can easily burn from about 8 GPH to 25 GPH depending on how I run it. If the EFIS engine monitor sends the data to the GTN it is always correct for the current power setting.

Rob Hickman
07-11-2012, 05:48 PM
This picture shows the data from the EFIS being sent to the GTN-650

91

Rob Hickman
07-11-2012, 05:56 PM
If you really want to enter the fuel and do some calculation on the GTN-650 you can use the Fuel Planning utility in the GTN-650 and uncheck the Use Sensor Data button.

92

art.pileggi
07-11-2012, 07:51 PM
Bob,

Thanks for the quick response. It would appear the 5600 is more sophisticated than Tecnam realized since they kept telling me there was no fuel sensor information available to the GTN650 and nothing could be done to allow manual entry.

Art

Rob Hickman
07-11-2012, 09:19 PM
I will check with them in the morning and see what is connected. The fuel computer only uses the fuel flow transducer, do you see fuel flow on the EFIS Engine monitor ?

The fuel gauges use sensors in the fuel tanks and are not used for the totalizer.

art.pileggi
07-12-2012, 06:27 AM
Bob,

I just got the plane back after 2 months in the shop (they are having trouble connecting the avionics together) and so I only did some ground tests to see if some of the problems were fixed. They still haven't figured how to switch the Pro Pilot between the 5600 and the GTN650 (the autopilot will not operate unless the GTN650 is turned on and has a flight plan entered). They are taking the position that the Pro Pilot will not work with the 5600 and I should have ordered the AF-Pilot. The bottom line is the plane is back in their shop so I can't give you the information you requested.

Art

Rob Hickman
07-12-2012, 03:34 PM
Your plane does have the fuel flow transducer and it is working correctly. We just made an EFIS software change so that the Trio Autopilot will switch sources, it should be good to go.

art.pileggi
07-13-2012, 05:34 AM
We just made an EFIS software change so that the Trio Autopilot will switch sources, it should be good to go.

Bob,

I am confused. The Trio is supposed to be connected to a 3 pole (ARINC A, ARINC B, RS232) double throw switch to either the 5600 or the GTN650. If on startup the switch is set to connect the autopilot to the 5600 and the power has already been removed from the GTN650, what is stopping the autopilot from talking to the 5600 until power is applied to the GTN650? For that matter, how does the autopilot even know the GTN650 exists?

Art

Rob Hickman
07-13-2012, 08:19 AM
The switch should normally be in the EFIS mode, most people don’t even install it. The EFIS CRS button will select the source for the CDI and Autopilot. If you select GNAV1 the flight plan from your GTN650 will be used. When you select GPS2 and enter a flight plan in the EFIS the AF-GPS puck will be used and sent to the autopilot.

The RS232 for the Trio was wired directly to the GTN650 in your plane, it is fixed now.

art.pileggi
07-13-2012, 08:41 AM
The RS232 for the Trio was wired directly to the GTN650 in your plane, it is fixed now.

Bob,

Since the autopilot would accept steering commands from the 5600 (alt and heading) but would ignore the any internal flight plan in the 5600, I suggested the RS232 as a cause for the problems over 3 months ago, but I was told everthing was wired correctly and working properly and I just didn't understand how to use it.

Thank you for getting involved. Without you help I don't think the planes problems would ever have been resolved.

Art