This is the sort of accuracy you can expect with the Floscan 201 transducer used by almost all GA totaliser systems.
It’s good enough 
The LFOB parameter is the primary factor on any long flight (well, apart from Vs).
It screams for a GFC500
Only if it is somebody else’s plane. If it is yours, you will be a few tens of k € poorer, you will have months of downtime, then various “little problems”, the plane won’t go any faster, and you have concentrated lots of points of failure into a single box
Maybe, maybe not. The GFC500 is extremely popular for a reason. And touring/traveling with or without a good autopilot is a world of difference.
A working autopilot, for sure.
The key Q to ask oneself is this: how is Peter managing to get a nearly 0% downtime on his TB20, and fly IFR all over Europe, despite the 1990s avionics?
I see lots and lots of people with “broken” planes and “broken” maintenance arrangements, basically dysfunctional stuff all around, and what do they do? They spend 50k on an avionics refit
What they are really doing is paying 50k to not have a plane to fly for a few months, which gives them peace of mind and enables them to worry about other stuff.
Mateusz wrote:
I think in many cases I could happily trade another 10 gallons against extra baggage, if I only ever find a reliable way of ensuring I am taking off with exactly 40 gal in these low wing, difficult to dip tanks.
I agree with @dublinpilot get a dipstick for measuring the fuel on the ground. Or do as suggested: Empty one tank, fill it up with known quantities in 10 liter increments and notice both the dipstick position and the fuel indication position. This is anyway what you need to do to calibrate the dipstick. Once that is done, the dipstick works really well and quick on the ground.
Also I hear the fuel quantity indicators on the EDM is much more accurate than the original gauges, but you can verify that using that method. It’s already cool to have the filler neck on those Pipers, one of the better ideas they ever had.
Can your analyzer feed the GPS? If so, that is a big advantage as you can get fuel estimates for the destination. But then again, the EDM does show you time remaining and you can easily compare that with the flight time remaining by the GPS.
dublinpilot wrote:
I’d also suggest that for the next while you take a note of the fuel before flight and after flight along with the flight time, ground time, altitude flown and tacho to get to understand what fuel you are really burning.
To note actual used fuel is always a really good idea.
Getting to know the quirks and specialties of any airplane will be one of the great learning experiences but also big fun. Also it will be interesting to read through the manual and figure out the sweet spots in performance and you will get to know your plane really well before too long.
Mateusz wrote:
Again, what are your experiences? What kind of accuracy can you expect from such a dipstick in a Piper?
I can usually estimate my fuel burnt in flight to around 5 ltrs based on my recording history history and using my self calibrated dipstick.
But there are exceptions. So you can never have the same confidence as you can have with a totaliser.
If you already have a totaliser then this is just a method to make sure you are starting with a correct fuel quantity.
But then again, the EDM does show you time remaining and you can easily compare that with the flight time remaining by the GPS.
The way a fuel totaliser is used is not like that. That was the old way of flying (time + or – at each waypoint, etc). The fuel data is sent by the totaliser to the GPS and the GPS displays the LFOB continuously. You then make in-flight decisions (if any are needed) based on that. The LFOB is the primary parameter for the flight.
The flight progress, by time or distance, is not generally relevant unless the ETA is relevant to the destination closing time.
So it is very simple.
Peter wrote:
The key Q to ask oneself is this: how is Peter managing to get a nearly 0% downtime on his TB20, and fly IFR all over Europe, despite the 1990s avionics?
That’s because you have top of the line 1990’s avionics. And you have done upgrades, including the EHSI and 8.33 kHz radios.
Peter wrote:
The way a fuel totaliser is used is not like that. That was the old way of flying (time + or – at each waypoint, etc). The fuel data is sent by the totaliser to the GPS and the GPS displays the LFOB continuously. You then make in-flight decisions (if any are needed) based on that.
Yes, that is how mine works as well, a miniflow which is connected to my GPS. Obviously that is much nicer.
However, I am not sure if @Matheusz ‘s EDM is connected to his GPS or not. If it isn’t (and possibly can not) than the EDM still gives him the current fuel flow, fuel on board and fuel remaining as well as a calculated endurance at the current power setting. If that is not fed to the GPS, you won’t get the estimated FOB on arrival, but you can MANUALLY compare the EET remaining with the Endurance and see how much time reserve you have.
I fully agree that it makes a lot of sense to connect the two, but it is not always the case. I’ve recently seen a PA28 which had a JP fuel computer which was not connected to the on board GPS as the GPS was a panel mounted hand held which can not legally be connected to an internal system.
If I read the manual correctly, the Arrow VI at 65% power has an economy cruise speed of approximately 130 kts @10k ft at 9.2 GPH or best power of about 138 kts @10k ft and 10.4 GPH, which also in the range table yields a range of 850-900 NM. With 55% at 14000 ft he could get about 50-100 NM more out of it (45’ reserve values).
So with a separated system my policy would be to keep 1 hr difference between endurance and EET as a minimum in flight, which would result in approximately 10 USG remaining at landing. 20 USG would be 2 hours difference and so on.
EDM is connected to his GPS or not.
It is just 1 wire plus ground. One-way RS232. The OP has a GNS430 which deffo supports this.
as the GPS was a panel mounted hand held which can not legally be connected to an internal system.
I doubt if any handheld will take the fuel totaliser data stream.
Otherwise, you can definitely connect handhelds to avionics. For example it is normal to connect a Garmin 496 to the intercom for GPWS warnings. I have an Aera 660 thus connected. Lots of other stuff… There is the position that anything not in the IMs and not STCd is illegal but that just means one has to find another installer
Traditional fuel calculations are horrible. With luck, within 10%. It works because most people fly within “bladder limits” i.e. say 2hrs But that greatly reduces the value of a decent plane like this.
Welcome to the Arrow brotherhood! I’m late to the game here, but congratulations and best of luck!
Any Arrow- (or Sweden) related questions, feel free to PM!
