Ok, then it´1 about 4 times too much fuel consumption as expected by the circle…
I wonder, how out real world pilots setup fuel before flight. I understand that winds and throttle setup / mixture control will also have an impact on your max range. But what is this circle calculating exactly then? If you do longer trips in GA, how do you plan your route to do some “in between” stops to re-fuel? I mean, just filling the plane up to 100% “just to be sure” also is no real solution…
Well there is still wind, weight, speed and your initial climb that could make a difference.
Especially if you only had 10% fuel, I think you can easily loose a lot of range if you climb a bit too high.
I don’t know how they do it IRL, I guess charts and calculations. 
For the A320 I use online fuel planner tools. I don’t know any for GA though.
Yes, charts and calulations. A circle would never cut it… Speeds, load, winds, fuel burn expectation,
Gives you kind of a good idea I suppose. But, the further you fly, the more wrong it’s going to be, and, with winds, it can’t possibly be correct in the first place. It would be this all weird shape depending on your cruising altitude and the wind speed. Ever wonder why trips east go so much faster?
Uhm, how long trips towards east do you mean? Is it maybe because of crossing some timezones, east is always earlier?
I’m talking airliners, trips over say an hour or two long or longer. It’s the jet stream. A constant river of air from west to east, so, the length of flight is pretty much always much faster when traveling east in an airliner in terms of how many hours it takes to fly the trip. These streams of air are typically at around 30,000 feet.
Just to avoid confusion, winds at 3000 feet also have an influence on your aircraft performance. 
I was just at 2.000 ft…
but i think i start to understand more and more.
I would opt for two range circles, one including 30 min (jet) or 45 min (prop) final reserve and one without.
If it’s really going to work, It really needs to also ask what your cruising altitude is going to be, as well as your load. Those would be minimum requirements. And it wouldn’t be a circle.
I don’t know how they could explain to people this is just an extremely rough estimate that will largely depend on how you fly the plane, even if it is going to take into account winds. It could be off by 70% or more depending on a variety of factors.
Nobody knows what the range circle represents. There is not just one range for an aircraft as there are many variables:
I suspect the range circle is what the manufacturer uses for marketing purposes so in best case scenario. In real life for a small GA aircraft weight does not have a big influence on fuel consumption so all calculations are normally performed at max. weight (as are the charts in the aircraft AFM), the altitude to fly is normally chosen based on airspace structure when flying VFR or airway structure when flying IFR. Then calculate the GS by correcting the TAS for forecasted wind at that altitude times the fuel consumption from the AFM tables.
Minimum altitude is based on obstacles and terrain, when required corrected for low temperature, non-standard pressure and windspeed vs terrain height in mountainous areas. Maximum altitude might be limited due to supplemental oxygen requirements.
For airliners its much more complex as there are different take-off and climb-out techniques, de-rates to reduce engine wear but increase overall fuel consumption, carrying extra fuel to reduce fuel costs at destination if the fuel is considerably more expensive (this is also a complex situation by itself as it costs fuel to carry fuel, there is a break-even point somewhere depending on fuel carried and difference in fuel price), different cruise techniques, optimum altitudes while also taking into account wind effects just to name a few.
On a large aircraft the aircraft weight has a huge effect on fuel consumption and thus range. I have done manual calculations in real life and it works best in this case to work backwards. So from alternate arriving with final reserve fuel + extra fuel, then calculate back to the destination and calculate back to the departure aerodrome. Normally the manufacturer has simplified charts included into the AFM which gives you the “sector” fuel taking into account the weight at the start, flight level, a correction for wind and separate tables for ISA -10C, ISA, ISA+10C, … etc. Otherwise you need to calculate the take-off, climb, cruise, descent and approach fuel separately, that’s a real mess 
.
Luckily the airline normally prepares those papers, normally it includes a table with the effect of altitude on time and fuel, so filed level +1000 ft, +2000 ft, …, and same for below. Often there is some text showing loss / gain in euros / dollars per ton of extra fuel uplifted and a correction table to correct for higher / lower take-off weight than planned as deciding to take some extra fuel for example will otherwise render the whole calculation useless.
So it is pretty much impossible to show the range accurately on a map taking into account all the variables. On my EFB in real life I can draw circles based on groundspeed and time, in practice I only use those to determine if I can use something as an alternate (max. 1 hr in still air, one-engine out, ISA for non-ETOPS) otherwise there isn’t much use in them.
Wow… THAT was detailed.
Thank you very much!
I start to get an idea.
So what do you recommend for the sim and GA VFR setups?
How can i tell approximately, if i can survive/arrive at the desired destination and/or how much fuel i should setup, to be on the safe side. And then, how to plan longer flights, when i can´t take10 times the needed fuel - as this circled “somehow guesses” - to be super-safe?
Well to start with you legally need the following:
You can normally find those figures in the aircraft AFM. For the aircraft I flew in flight school and as an instructor for example the taxi fuel was standard 4 liters, there was a table for climb time, distance and fuel, cruise performance, there where no tables for descent performance so we used cruise consumption for the descent as worst case. I think this is quite typical for smaller GA aircraft. Weight for all those tables is max. take-off weight so that takes a lot of complexity away.
Below you can see an example of cruise performance charts:
So lets say flying at 4000 ft with best economy mixture at 2450 RPM = 90 kts CAS and 27 ltr/hr consumption. Unless you make very long climbs you don’t really need to take the climb fuel into account as the higher fuel consumption is compensated for by lower fuel consumption in the descent, the difference is negligible in most planes. If you want to make it really simple you could divide the useable fuel quantity by 27 ltr/hr and you know the endurance of the aircraft. Endurance x groundspeed = range. But as soon as you change heading the groundspeed will change and so does the range.
This is why in real life you normally calculate the groundspeed, time and fuel burn per leg. The fuel consumption and CAS doesn’t change per leg so that is easy as long as you keep flying at 4000 ft, the TAS will not change considerably on short GA flights so you could calculate that once and use for all the legs, then there is only the track and TAS vs forecasted wind speed and direction to calculate the heading to fly (including wind correction angle) and ground speed. But that might be a little overkill for use in MSFS.
To give you an idea, this is an example of a real world flight preparation, it is an IFR plan on a small Single Engine Piston plane but the principles are the same for VFR. Bottomline is that there is a lot of planning involved concerning take-off & landing performance, weight & balance, navigation and fuel for even a simple VFR flight… But I guess there are loads of Apps available for this nowadays, the times of measuring distance and tracks on a chart with a protractor and calculating the groundspeed and heading to fly with a flight calculator are over 
.
Thank you very very very much.
That was very instructive info for me!
I think, i start to get more and more the idea, what real aviation is about.
I have to say, i think in am flying much more like a butterfly, having an idea where i wanna start and where to land, but on my route i fly a bit here to see whats to see, then a little bit there, to see what´s there, then a bit up, then a bit down, then a circle to maybe see some attraction once more… So my flightpath may look like drawn by an wild chimp somehow, as it can´t be very economic or cost efficient.
Your post opened my eyes somehow.
I start to understand, that my “style of flying” seems to be a bit “unconventional”, to say at least. This, as i understood from your post, lets my fuel consumption rise up to some levels, noone ever will be able to calculate before takeoff.
So for longer trips i need to stay a bit more to the planned route or take some petrol cans with me, not to run out of fuel again.
So my next challenge seems to be, to find such performance data for my favorite GAs and maybe also the data of their MSFS equivalent. I think, not all planes have the real world stats and data implemented perfectly yet, there seem to be some differences and/or changes/bugs so far.
If anyone knows a way to maybe read such stats from some MSFS files, that would be a great hint. So we could check, what stat´s currently there are in the sim to check them with the real world.
Edit: your flightplan shows a german route? Is it just an example or do you fly there in real life?
Thanks for that… nope, the typical GA pilot can often fly much like a butterfly, why else would we fly but to have fun and explore? I pity the man whose all business when they are on their own time. Just last Sunday, I did my first solo flight in 19 years, and flew up to Lake Winnipesaukee, had lunch at the airport on the shore there, took off, flew around the lake and checked out where an old airport used to be that I used to fly into, then flew to another airport at White river junction, and flew home in the dark… Great day, perfect day for flying
It is still important to plan your day, though, that flight has been a month in the making… not that it took that long to plan, but it did take me a couple of hours to prep for it.
Well the whole purpose of flying VFR is the ability to fly around without a real flight plan and take scenic routes, but in such cases you’ll still need to keep an eye on fuel consumption and range remaining in order to land at the destination with the required reserve. My example is a little too black and white maybe, its more the airline way of doing things.
When I was flying VFR myself or instructing VFR we would normally have a complete route planned, then you’ll at least know the minimum required fuel and time to destination. If you substract the minimum required fuel from the total fuel onboard you will get an idea how much extra time you have to “fool around” 
. We often changed plans in flight and practiced unplanned diversions, in any case we always recalculated the fuel.
The example is from when I was a flight instructor. We flew in a lot of places within Europe. I still do but I left the Single Engine Piston days behind me long time ago, now it is primarily pushing buttons and drinking coffee .
Some good news… I just completed a couple long flights in the 748 and after this latest update it appears the range issue (at least for the 748) had been fixed.
I flew over 8 hrs and used about 1/2 the fuel from a 100% full tank. Now long flights can be accomplished more realistically. Thank you!!
Yay, good to hear, i´m not the only butterfly out there…
Do you guys happen to know or even use “Little Navmap”? It´s a flight planning tool, which seems to be extremely useful, but still blows my mind, as i´m totally new to it. I found out, it also is able to calculate fuel usage, depending on the used planes performance and possibly also to the personal style of fuel efficiency, if you record a flight and let the tool calculate the usage.
So far about it in theory, but i´m just scratching it´s surface a bit so far.
Does anyone of you have some experience with it?
