D120 "fuel at waypoint" reading reads zero

[jcash1]

I have a D-100 and D-120 in my RV-7A with about 45 hours on the airplane. The "fuel at waypoint" was reading accurately until yesterday, and on two flights with a destination selected in the Garmin 430 it read zero. All the other readings worked as before, including those presenting data required to compute the fuel at waypoint. Is there a reset, or something else I need to do to cause the fuel computer to generate this reading if all the required data is available. Thanks, Jim.

 

[DBRV10]

Sounds like the Dynon system is not getting the Garmin data. Does the HSI work?

 

[dynonsupport]

If the current "gallons remaining" is lower than what are really in the tanks, that would cause the fuel at waypoint to also read lower than you're expecting. You do need to reset that at every fill up. Any chance that's it?

 

[jcash1]

I think this is what is happening, but I have to fly the bird to check it out. I have the HS34 that has a function that allows you to pick the nav source. The problem may be as simple as when nav (for VOR or LOC is selected, it cuts off the input from the GPS to the Dynon. If that is the case, you would lose the aircraft the speed input, so the computer could not compute the time and amount of fuel used to the waypoint. I will post the result as soon as I can fly the bird again. It will be a week or so. Jim

 

[jcash1]

This one was easy. If NAV is selected on the HS34, GPS data is not provided to the fuel computer, and the "fuel at waypoint" is no longer computed. The answer is to simply select "GPS". Seems to me this is an anomely that should be corrected. Jim

 

[dynonsupport]

Just put this on the list of things to look into in our next firmware turn. Can't promise anything, as usual.

 

[dynonsupport]

Jimmy,

We looked into this and have the following questions/comments.

Fuel at waypoint is not provided when using a VOR because distance to waypoint is not known unless you are navigating with the GPS. But the fuel totalizer and such should work fine, are they?

So if only the Fuel at waypoint isn't working in your fuel computer, that is expected. Also, we did verify functionality here and everything checks out ok.

So I think we are ok here, but let us know so we can better understand if there is a real issue.

 

[jcash1]

That is exactily right. Everything else worked except "fuel at waypoint". For me, it was just a matter of undertanding the sytem. It presents no real problem. Jim

 

[dynonsupport]

Thanks Jimmy, great. Happy flying.