Fuel Tank Calibration, Fuel Flow Test, and ADHARS Calibration

TLDR

• Calibrated ADHARS on both G3X and G5
• Conducted Fuel Calibration
• Conducted Fuel Flow Test

Details

ADHARS Calibration

I conducted ADHARS calibration on both the G3X and G5.

To do that, I needed to adjust to airplane to be perfectly level. Per the maintenance manual, the ground level is achieved by making the second line of rivet below the window horizontal to the ground.

I used a laser level to measure it, and the nose was a little too high. So I deflected the nose wheel just enough to drop the nose to the required amount so the rivet line became horizontal.

Then I turned on both G3X and G5 in their configuration mode, and selected ADHARS calibration on both. Each one took 30 seconds and reported calibration success.

Fuel Calibration

To do the fuel calibration, I bought 20 gals of UL94 from the airport FBO, and used a 2 GAL tank to transfer the fuel into the tank for calibration.

The calibration process was striaghtforward but took a long time because I had to transfer a lot of fuel from one tank to another manually..

To complete the calibration process, I set the G3X in configuration mode. Then I put in 2 gals at a time, and wait for the fuel sender to stabilize and record the calibration point. Then I repeated this process until the fuel sender readings stopped change. On the left tank this was 12-14 gals, and the right tank stopped changing at 16 gals.

Then I saved the calibration. I agree with what everyone else said, the reading looked wildly inaccurate, and I do not plan to use it as my primary source for fuel reading. I think the Rotax ECU’s reading will be much more reliable.

Fuel Flow Test

With fuel in the tank, I was finally able to do the fuel flow test. It felt quite scary when the fuel flew through the hoses for the very first time. I invited my friend/hangar neighbor Brain to come and walk me through with his A&P knowledge.

So we started with the left tank (ie, left boost pump), and with one Rotax pump on the other off. I pumped 2 gals of fuel when measuring the time spent. Then we turned on the other Rotax pump and tested again. I did the right tank by myself following similar steps.

The result is as the following, which is more than what AC43.13B required (125% of max flow rates for fuel pumped system):