Fuel Guage w/o Fuel Sensors

[darnold]

I recently replaced the EFIS that came standard in my aircraft (a German made Brauniger) with the D180.  I am really pleased with the D180.  The one area of "disappointment" is that on the primary EMS screen you are unable to see what the Fuel Level is if you do not have Fuel Level Sensors installed.  Unfortunately in my aircraft retrofitting fuel sensors is not an option.  

However, it would still be great to see (preferrably in the form of a guage) how much fuel is remaining (I would settle for the text read-out on the primary EMS page under the fuel flow read-out, but a graphic representation would be much better).  This however does not appear to be an option without fuel sensors installed.  This is the one piece of information my old EFIS/EMS presented graphically on the main screen (it provided an estimate in the form of a "bar graph") that I miss and would love to see added in future firmware releases.

 

[dynonsupport]

Well alternatively, if you install the fuel flow sensor, the fuel computer can compute the total fuel remaining (based on what you started and flow) as a textual info item.

Fuel quantity sensors are one of a few FAA requirements for all airplanes, and so to eliminate any confusion, the graphical and textual elements that depict per-tank fuel quantity will always be based on a sensor measurement of some kind. Estimating fuel level is also not really easily done - burn rate changes significantly with differences in mixture setting, altitude, and so on. We frankly do not think it's a good idea to present estimates on a device that is designed to be a fairly precise measurement tool.

Estimating fuel quantity is probably best done with a simple timer and a heavy dose of skepticism if you do not have any way of measuring the actual quantities in-tank while in flight.

 

[darnold]

Thank you for the response.  The CTsw (at least the European specification) comes with site guages and it would be extremely difficult to fit fuel sensors in each of the wing tanks.  So unfortunately this is not an option for me.

I am also a bit confused by your statement "We frankly do not think it's a good idea to present estimates on a device that is designed to be a fairly precise measurement tool." since you already are doing exactly that on the Fuel page.  The Dynon presents a litres (or gallons) remaining figure on this page (in text form) and it presents/calculates this figure without fuel sensors installed (LTRS REM), at least it does on mine.  I assume it is making this calculation from the amount of fuel you tell it are in the tanks (e.g., when you add fuel) and then using the fuel flow sensor estimates what is remaining as you consume it.  In my experience the Dynon is providing a fairly accurate estimate of the fuel remaining in my aircraft since I have accurately calibrated the fuel flow sensor. In flight I simply cross check what the Dynon has estimated is remaining with what the site guages are telling me.

Presently, if you do not have fuel sensors you get a blank space on the EMS page where the fuel guages would normally be, but you certainly get an estimate of fuel remaining as a textual item on the Fuel page only.  My suggestion, for even greater ease, therefore would be that it would be nice, if you do not have the fuel sensors installed, to present this peice of information on the EMS page as well as the Fuel page (in place of the "missing" fuel guages).  It would be great if it could be graphically represented but I would settle for a simple text figure (e.g., under the fuel flow textual info item).
 
Just a suggestion.

Cheers,
Dean

 

[malko05]

Hello Dynon,

Will it be possible in a new firmware to put the fuel computer remaining value instead of a blank space on the EMS page (I dont have the fuel probe) ??

 

[PhantomPholly]

We frankly do not think it's a good idea to present estimates on a device that is designed to be a fairly precise measurement tool.

I'll have to go along with some of the other opinions here - the fuel flow rate sensor is a digital device that is probably far superior to your typical capacitance sender, particularly when fuel is sloshing around in the tank being measured. It's a shame you can't put that on the primary display, perhaps with a disclaimer of "Est. Fuel Remain."

The only down side to using "fuel remaining" as your PRIMARY indication of fuel is that it is not a DIRECT measurement - it relies upon the pilot remembering to set the initial fuel total before takeoff. If (and only if) the pilot has done this, that value should be more accurate (once calibrated) than any capacitance sender.

 

[dynonsupport]

Malko, we have no plans to update the current EMS to suport this. The new SkyView system will be able to do this because all elements on the EMS screen can be moved by the user.

 

[malko05]

Thank you for answering.

Unfortunatly the D180 size is the maximum size for an efis in my plane (Pulsar)....

 

[dynonsupport]

For your information, The 7" SkyView is only slightly larger than the D180, mostly to accommodate the knobs at the bottom of the screen.