Fuel Circles
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At the risk of starting another thread on this... "excessive" leaning is a danger only at high power settings e.g. 75% or higher, specifically ones which result in high CHTs (perhaps 500F or so).
Excessive leaning alone just gives you a rough engine and a loss of power. No damage is caused.
During taxi, maximum possible leaning is the best thing - keeps the plugs clean.
Excessive leaning alone just gives you a rough engine and a loss of power. No damage is caused.
During taxi, maximum possible leaning is the best thing - keeps the plugs clean.
I was surprised how many people didn't understand the difference between density and specific gravity, particularly when using US gallons.
What is the difference?
What is the difference?
Specific gravity is a ratio of the mass of a material to the mass of an equal volume of water. As it is a dimensionless ratio, it has no units.
I think pre-planned fuel circles make perfect sense if you are flying a high performance jet on a low level NAVEX where things happen fast and wind has a relatively small effect on flight time. They IMO make no sense in the context of a PPL flying your average Cessna or Piper.
From the very first lesson I teach my students to think about fuel as "time in your tanks". This of course starts with what the dipstick shows on the preflight. Lessons which are flown in the local area use a block fuel burn (ie a conservative average of what is typical for an average training sortie, which is usually about 20 % higher than the leaned cruise fuel flow in the POH), giving the time available in the air for that lesson. This time minus the reserve is the "we have to be on the ground no later than" time.
Navigation exercises are planned in the usual way but I insist that the student be able to tell me how long they can fly from the top of climb point. Have to go somewhere else from any point in the flight ? Well after you figure out how long it is going to take you you can ask yourself "do I have that time in the tanks". This is really useful when you have a GPS (which IMO is mandatory equipment now) because you can get instantaneous ETE information to anywhere (obviously to be double checked early for any GS changes caused by changing your heading)
As for fuel gauges, I intensely dislike the blanket assertion that "fuel gauges are useless".
If you go to the POH for any Cessna there is an equipment list that specifies what equipment is "required". On that list is fuel gauges. If you are flying a Cessna and the fuel gauges are not working then the aircraft is not being operated in accordance with its type certificate.
My experience is that light aircraft fuel gauges particularly the ones in Cessna's are not particularly accurate at the top of the travel but once you get to 1/3 or less quantities they actually are pretty good. If you own an aircraft it would seem foolish to me not to calibrate the gauges by draining the tanks and filling them in 5 gal increments.
Unfortunately if you are renting some beater from the flying school you do not have much control over the state of the gauges but you can still get a feel for what they are saying by comparing the dipped amount to what is showing on the gauges. This simple check is almost never taught in flying schools. If you are filling the aircraft with full fuel after your flight, before adding fuel estimate what you think you burned and compare it to the pump meter.
If it is your own aircraft or a rental where you usually fly the same aircraft, with a bit of experience you can get consistently pretty close.
From the very first lesson I teach my students to think about fuel as "time in your tanks". This of course starts with what the dipstick shows on the preflight. Lessons which are flown in the local area use a block fuel burn (ie a conservative average of what is typical for an average training sortie, which is usually about 20 % higher than the leaned cruise fuel flow in the POH), giving the time available in the air for that lesson. This time minus the reserve is the "we have to be on the ground no later than" time.
Navigation exercises are planned in the usual way but I insist that the student be able to tell me how long they can fly from the top of climb point. Have to go somewhere else from any point in the flight ? Well after you figure out how long it is going to take you you can ask yourself "do I have that time in the tanks". This is really useful when you have a GPS (which IMO is mandatory equipment now) because you can get instantaneous ETE information to anywhere (obviously to be double checked early for any GS changes caused by changing your heading)
As for fuel gauges, I intensely dislike the blanket assertion that "fuel gauges are useless".
If you go to the POH for any Cessna there is an equipment list that specifies what equipment is "required". On that list is fuel gauges. If you are flying a Cessna and the fuel gauges are not working then the aircraft is not being operated in accordance with its type certificate.
My experience is that light aircraft fuel gauges particularly the ones in Cessna's are not particularly accurate at the top of the travel but once you get to 1/3 or less quantities they actually are pretty good. If you own an aircraft it would seem foolish to me not to calibrate the gauges by draining the tanks and filling them in 5 gal increments.
Unfortunately if you are renting some beater from the flying school you do not have much control over the state of the gauges but you can still get a feel for what they are saying by comparing the dipped amount to what is showing on the gauges. This simple check is almost never taught in flying schools. If you are filling the aircraft with full fuel after your flight, before adding fuel estimate what you think you burned and compare it to the pump meter.
If it is your own aircraft or a rental where you usually fly the same aircraft, with a bit of experience you can get consistently pretty close.
Last edited by Big Pistons Forever; 16th Jan 2012 at 22:26.
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Our fuel gauges are as accurate as they come, but I wouldn't want to rely on them. Pointers can stick. There are only two gauges with three-way toggle switches, so you don't see all tanks in one glance.
Our plane has six tanks and we switch manually between them using two separate fuel selectors (one for each wing with three positions each). To keep track of our fuel state at any time, we log a detailed record of the contents of each tank, the dip-checked amounts, the fuel used and the fuel remaining before and after each flight, plus the fuel used from each tank between switches, in a separate "fuel log".
NO WAY we wanted to risk getting caught out not knowing *exactly* what our fuel state is or getting in trouble like some unfortunate pilots in the Comanche's long history have. Without keeping some record, it is just too easy too make a bad mistake!
Some Comanche pilots like to avoid trouble by just flying on the main tanks with both switches selected ON, effectively reducing the need to switch. One problem with this is that you don't know from which tank the engine is actually feeding. Another problem is that the mechanical fuel pump's efficiency can lead to fuel crossfeeding from one wing to the other via the central sump. Things like unusual attitudes, turns, and having the electrical fuel pump on further complicate matters, until you end up having no idea at all how much fuel is in which tank while you are flying. Since we don't want to refuel after each flight, which is pretty ridiculous after a one hour flight when you have 10+hours endurance, this way of operating is not suitable for us.
We have a wonderful instrument called the Shadin Miniflo fuel computer. Besides being an invaluable aid in leaning the mixture correctly, it plays an important role in our fuel planning and logging.
Before a flight we plog our expected fuel usage at the planned power settings for the planned legs of our route, expected time to climb, cruise, descend, etc. and we set a procedure for the order in which the tanks are switched and the times to run on a tank given our load balancing needs (This is useful because we have a wide wingspan and 30 minutes flying on a tip tank makes quite a big difference).
We then fly following our planned switches and we note the amounts used at each switch.
This all may sound like a lot of work, but the workload is minimal and just part of our normal operating procedure at the time of the walkaround (dipping and logging) and writing down the amount used at the times a tank is switched. We like the way it automatically adds awareness of our fuel safety. Double-checking the fuel computer against dip-checked amonts and uplifted amounts gives us several opportunities to spot errors in resetting the fuel computer or calculating errors in the log.
In November I got ramp checked. Among other things I was asked to produce proof that I had planned my flight with sufficient range. This was a bit of a laugh because there was about eight hours remaining in the tanks when he asked. When I showed him the fuel log he was so stunned that I wondered if he had ever seen one before. The C414B I have been privileged to get acquainted with had eight tanks to keep track of, so the need for some kind of procedure is not unique to the Comanche.
Most light aircraft have only two tanks, but I know of several types that have long range capacity and extra tanks so for these fuel mismanagement risks might be mitigated by strict procedures as well.
Our plane has six tanks and we switch manually between them using two separate fuel selectors (one for each wing with three positions each). To keep track of our fuel state at any time, we log a detailed record of the contents of each tank, the dip-checked amounts, the fuel used and the fuel remaining before and after each flight, plus the fuel used from each tank between switches, in a separate "fuel log".
NO WAY we wanted to risk getting caught out not knowing *exactly* what our fuel state is or getting in trouble like some unfortunate pilots in the Comanche's long history have. Without keeping some record, it is just too easy too make a bad mistake!
Some Comanche pilots like to avoid trouble by just flying on the main tanks with both switches selected ON, effectively reducing the need to switch. One problem with this is that you don't know from which tank the engine is actually feeding. Another problem is that the mechanical fuel pump's efficiency can lead to fuel crossfeeding from one wing to the other via the central sump. Things like unusual attitudes, turns, and having the electrical fuel pump on further complicate matters, until you end up having no idea at all how much fuel is in which tank while you are flying. Since we don't want to refuel after each flight, which is pretty ridiculous after a one hour flight when you have 10+hours endurance, this way of operating is not suitable for us.
We have a wonderful instrument called the Shadin Miniflo fuel computer. Besides being an invaluable aid in leaning the mixture correctly, it plays an important role in our fuel planning and logging.
Before a flight we plog our expected fuel usage at the planned power settings for the planned legs of our route, expected time to climb, cruise, descend, etc. and we set a procedure for the order in which the tanks are switched and the times to run on a tank given our load balancing needs (This is useful because we have a wide wingspan and 30 minutes flying on a tip tank makes quite a big difference).
We then fly following our planned switches and we note the amounts used at each switch.
This all may sound like a lot of work, but the workload is minimal and just part of our normal operating procedure at the time of the walkaround (dipping and logging) and writing down the amount used at the times a tank is switched. We like the way it automatically adds awareness of our fuel safety. Double-checking the fuel computer against dip-checked amonts and uplifted amounts gives us several opportunities to spot errors in resetting the fuel computer or calculating errors in the log.
In November I got ramp checked. Among other things I was asked to produce proof that I had planned my flight with sufficient range. This was a bit of a laugh because there was about eight hours remaining in the tanks when he asked. When I showed him the fuel log he was so stunned that I wondered if he had ever seen one before. The C414B I have been privileged to get acquainted with had eight tanks to keep track of, so the need for some kind of procedure is not unique to the Comanche.
Most light aircraft have only two tanks, but I know of several types that have long range capacity and extra tanks so for these fuel mismanagement risks might be mitigated by strict procedures as well.
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From the very first lesson I teach my students to think about fuel as "time in your tanks". This of course starts with what the dipstick shows on the preflight. Lessons which are flown in the local area use a block fuel burn (ie a conservative average of what is typical for an average training sortie, which is usually about 20 % higher than the leaned cruise fuel flow in the POH), giving the time available in the air for that lesson. This time minus the reserve is the "we have to be on the ground no later than" time.
Navigation exercises are planned in the usual way but I insist that the student be able to tell me how long they can fly from the top of climb point. Have to go somewhere else from any point in the flight ? Well after you figure out how long it is going to take you you can ask yourself "do I have that time in the tanks".
Navigation exercises are planned in the usual way but I insist that the student be able to tell me how long they can fly from the top of climb point. Have to go somewhere else from any point in the flight ? Well after you figure out how long it is going to take you you can ask yourself "do I have that time in the tanks".
So this is really out of curiosity, nothing else. So ok, the student tells you how long they can fly from top of climb. THis I can do for my instructor by looking at fuel circles seeing we have say 57 litres for our trip and at that point we have enough in teh tank to RTB. It is there on my chart and all the brain work has been done before so I can just concentrate on flying. So I guess what i'm wondering is why form your viewpoint is asking the student to tell you this way when they are probably maxed out with flying, better than our way where my instructor can see from looking at his copy of my planned route, how much fuel I expect us to have?If we are flying one of the Grobs, we don't use a dipstick, but just check the fuel gauge against the Tech log. However, if we are flying the Firefly we do indeed dip both tanks.
And on the subject of leaning....I am not taught how to, the mixture is ALWAYS rich!
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HI GQ, I'm not really experienced enough to enter into the technical arguments here but I'm amazed at the difference in training between you 'down the road' as it were and what we do here, which in theory you would think would be broadly similar. I've honestly never heard of a fuel circle, we are taught to lean out at whatever altitude we are at and I personally always take off with full tanks, in fact we always keep the a/c tanks full for condensation prevention. You can never, in my opinion, have too much fuel. Obviously weight and balance considered and bearing in mind I don't fly jumbo jets.
Incidentally I was doing some NDB approaches at your place today, (it's free after all...:-) after ringing your tower mob and being assured they could fit me in at a specific time. I finished up doing four flogs round the holding pattern (in clag with a 30kt wind) before I got clearance. Total time to fly the 8nm to your place and the 8 nm back to mine was 1:30.....it would have been cheaper to go to Donny and pay my £4.50.
Incidentally I was doing some NDB approaches at your place today, (it's free after all...:-) after ringing your tower mob and being assured they could fit me in at a specific time. I finished up doing four flogs round the holding pattern (in clag with a 30kt wind) before I got clearance. Total time to fly the 8nm to your place and the 8 nm back to mine was 1:30.....it would have been cheaper to go to Donny and pay my £4.50.
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Hi Thing,
Maybe 'cos we have the RAF's Ab Initio guys our instructors are used to doing things the RAF way?! Thought there would be talk of fuel circles around your club house!
Anyway, incoming on your PM!
Maybe 'cos we have the RAF's Ab Initio guys our instructors are used to doing things the RAF way?!
Thought there would be talk of fuel circles around your club house!Anyway, incoming on your PM!
I was very interested in this Big Pistons. Of course I would not dream of arguing with you because from other threads I see that you are vastly experienced and respected on this forum. So this is really out of curiosity, nothing else. So ok, the student tells you how long they can fly from top of climb. THis I can do for my instructor by looking at fuel circles seeing we have say 57 litres for our trip and at that point we have enough in teh tank to RTB. It is there on my chart and all the brain work has been done before so I can just concentrate on flying. So I guess what i'm wondering is why form your viewpoint is asking the student to tell you this way when they are probably maxed out with flying, better than our way where my instructor can see from looking at his copy of my planned route, how much fuel I expect us to have?
If we are flying one of the Grobs, we don't use a dipstick, but just check the fuel gauge against the Tech log. However, if we are flying the Firefly we do indeed dip both tanks.
And on the subject of leaning....I am not taught how to, the mixture is ALWAYS rich!
So this is really out of curiosity, nothing else. So ok, the student tells you how long they can fly from top of climb. THis I can do for my instructor by looking at fuel circles seeing we have say 57 litres for our trip and at that point we have enough in teh tank to RTB. It is there on my chart and all the brain work has been done before so I can just concentrate on flying. So I guess what i'm wondering is why form your viewpoint is asking the student to tell you this way when they are probably maxed out with flying, better than our way where my instructor can see from looking at his copy of my planned route, how much fuel I expect us to have?If we are flying one of the Grobs, we don't use a dipstick, but just check the fuel gauge against the Tech log. However, if we are flying the Firefly we do indeed dip both tanks.
And on the subject of leaning....I am not taught how to, the mixture is ALWAYS rich!
There are few things in aviation that are black and white with "right" and "wrong" ways to do something. Navigation in particular is one where there are numerous acceptable ways to plan and execute a cross country trip. I think most experienced pilot settle on a way that works for them. Being rather lazy I am all for simple procedures where the level of accuracy is proportional to the accuracy requirement. The whole fuel circle thing just doesn't spin my prop......
However what ever method you use it is important that you truly understand what you are doing. From your post this does not appear to be the case. You say you want to RTB and no problem because you are on the 57 litre circle ? Well what about if you are on the crosswind leg or your triangle NAVEX with a 25 knot wind blowing from the direction of your base. Will that 57 litres allow you to fly with a 25 % lower ground speed ? I don't see how. The bottom line is the only thing that matters is the ETE compared to how much time you current fuel state will give you. In slow airplanes this can cause large changes in actual achievable range. When you are in a RAF fast jet doing 350 knots wind is basically irrelevant but it is most certainly relevant at 90 knots.
Finally if you always fly at full rich how do you know your fuel burn ? The POH in every light aircraft I have ever seem only gives you fuel flows with the mixture leaned as per the POH procedure. If you don't know how much you are burning then your circles are meaningless.
Don't get me wrong if this method appeals to you fill your boots but make sure you know what you are actually planning.
I am a big believer in the intelligent use of technology. The GPS is a very valuable aid and its nearest airport function can literally be a lifesaver. Knowing your exact GPS derived ETE is extremely helpfull and that combined with knowing how much time you can fly with the fuel in your tanks an easy calculation that is simply the total time in your tanks minus how long you have flown since top of climb, makes a diversion pretty straighforward.
Its even easier with a fuel totalizer with a GPS input, but a couple of hundred pound portable GPS and a watch are almost as good and can be used on any club rental.........
Last edited by Big Pistons Forever; 18th Jan 2012 at 23:09.
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Hmmm, i'm feeling this is starting to get a little out of my depth - still have lots to learn and don't mind admitting so!
However, in answer to Big Pistons (and I say again, I am not trying to argue with those more experienced, just stating what I am taught):
I have to disagree with this statement I am afraid as I believe I do indeed understand fuel circles..a fact on which my instructor agrees! RTB on say in this example I quoted a 72 litre circle. The 72 litre circle is the first circle where we have used 3 litres in taxi and climb to the RVP. if the engine was to go bang at this point, we would only require three more litres to RTB. If however, the engine went bang at the furthest point on the trip outlined, we would have 66 litres to RTB and the minimum red fuel is 56 litres. PLanned fuel useage on the return leg is about 9 litres, so we are well in board.
This of course is indeed in still air, and one would have to recalculate in flight if there was a 25kt headwind, or for diversion etc. Fuel burn? Grob uses 25 litres in 1 hour. I would need to check if this was fully rich or leaned. But as this is the figure I am taught to use, and my teaching is not to lean, it must be the fully rich figure.
I do stress though, I am not trying to pretend I know more than I do...just interested to see how others are taught and if the military/ex military pilots out there agree that this is a worthwhile system or whether they when flying privately use GPS!
However, in answer to Big Pistons (and I say again, I am not trying to argue with those more experienced, just stating what I am taught):
However what ever method you use it is important that you truly understand what you are doing. From your post this does not appear to be the case. You say you want to RTB and no problem because you are on the 57 litre circle ?
This of course is indeed in still air, and one would have to recalculate in flight if there was a 25kt headwind, or for diversion etc. Fuel burn? Grob uses 25 litres in 1 hour. I would need to check if this was fully rich or leaned. But as this is the figure I am taught to use, and my teaching is not to lean, it must be the fully rich figure.
I do stress though, I am not trying to pretend I know more than I do...just interested to see how others are taught and if the military/ex military pilots out there agree that this is a worthwhile system or whether they when flying privately use GPS!
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Still can't see why you're taught to fly full rich all the time unless you never get above 100 ft. I don't know the Grob so there may well be a perfectly valid technical reason.
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I'm not sure that you really do understand fuel circles.
What is the point of a technique which ignores wind and where the largest single input - fuel burn - is a gross approximation?
Last Saturday I flew a point to point flight of about 30 miles - it took me 2 hours because I took a pretty scenic route!
I took off with a wind of about 260/3kts. Midway the wind was about 210/12kts and when I landed it was 270/5kts. The bit in the middle would make the 'fuel circle' method hopelessly inaccurate. So too would the fact that I was so enjoying the view that I throttled back and used the wind to slope soar and loiter around the hills.
The critical aspect for light aircraft is that wind has a massive impact at 90kts. Last year I flew from my engineers back to my home base - ground speed for much of the flight - 45kts. On the ground it was about 260/25kts at 1000 foot very very much more - as shown by the GPS!
Calculating a set of range rings which are highly inaccurate simply does not seem to be a smart technique. Flying at 360 or 420 kts - ok I can ignore the wind flying at 90 kts it is one of the most significant inputs. Oh, along with the 'loud pedal'.
What is the point of a technique which ignores wind and where the largest single input - fuel burn - is a gross approximation?
Last Saturday I flew a point to point flight of about 30 miles - it took me 2 hours because I took a pretty scenic route!
I took off with a wind of about 260/3kts. Midway the wind was about 210/12kts and when I landed it was 270/5kts. The bit in the middle would make the 'fuel circle' method hopelessly inaccurate. So too would the fact that I was so enjoying the view that I throttled back and used the wind to slope soar and loiter around the hills.
The critical aspect for light aircraft is that wind has a massive impact at 90kts. Last year I flew from my engineers back to my home base - ground speed for much of the flight - 45kts. On the ground it was about 260/25kts at 1000 foot very very much more - as shown by the GPS!
Calculating a set of range rings which are highly inaccurate simply does not seem to be a smart technique. Flying at 360 or 420 kts - ok I can ignore the wind flying at 90 kts it is one of the most significant inputs. Oh, along with the 'loud pedal'.
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I think that may be the case Thing...as we've seen from other posts, there aren't that many other Grob "drivers" out there.....
One thought has just occurred though...maybe we just haven't cruised enough for me to be introduced to leaning? So far we have really only bimbled around the local area on GH trips. The Grob cruises at 2400RPM is that maybe too slow to lean?
Oh well, maybe I do, maybe I don't.
Bottom line is I need to understand the circle method cos thats the way i'm taught; and I daresay theres a reason for it. But i'm glad this thread is doing what I hoped it would - bring a little dicussion and controversy to PPruNE
One thought has just occurred though...maybe we just haven't cruised enough for me to be introduced to leaning? So far we have really only bimbled around the local area on GH trips. The Grob cruises at 2400RPM is that maybe too slow to lean?
Oh well, maybe I do, maybe I don't.
Bottom line is I need to understand the circle method cos thats the way i'm taught; and I daresay theres a reason for it. But i'm glad this thread is doing what I hoped it would - bring a little dicussion and controversy to PPruNE
Last edited by Grob Queen; 19th Jan 2012 at 19:22. Reason: Just seen new post
The problem is that the RAF is trying to apply a system which works for still/air low level high speed navigation, where W/V is of little consequence, to medium level navigation at low speed in the Plastic Pig, where W/V is highly significant.....
The same logic which uses MDR for pre-flight planning purposes, resulting in inaccurate GS values. It is actually OK to plan a low level navigation trip at 240 KIAS+ using still air, but to use MDR for pre-flight planning at 120KIAS is inadequate for GS calculations.
This is the 'running before you've learned to walk' approach, using elementary training aeroplanes for purposes for which they are quite unsuitable. Why? Because they can't afford to operate proper basic trainers such as the Jet Provost these days....
The same logic which uses MDR for pre-flight planning purposes, resulting in inaccurate GS values. It is actually OK to plan a low level navigation trip at 240 KIAS+ using still air, but to use MDR for pre-flight planning at 120KIAS is inadequate for GS calculations.
This is the 'running before you've learned to walk' approach, using elementary training aeroplanes for purposes for which they are quite unsuitable. Why? Because they can't afford to operate proper basic trainers such as the Jet Provost these days....
I remember back in my day they were known as the variable noise constant speed machine.
'Constant thrust, variable noise'!
We did some LL at 300KIAS, but that meant that you couldn't use the standard technique for regaining ETA without exceeding the engine limits. It was also a rock-hard ride and any significant turns at 60º AoB bled speed off considerably. It used a LOT of fuel and the controls were quite heavy, particularly in roll.
Whereas 240KIAS at 250 ft was a much better regime - and gave greater time at LL.
We did some LL at 300KIAS, but that meant that you couldn't use the standard technique for regaining ETA without exceeding the engine limits. It was also a rock-hard ride and any significant turns at 60º AoB bled speed off considerably. It used a LOT of fuel and the controls were quite heavy, particularly in roll.
Whereas 240KIAS at 250 ft was a much better regime - and gave greater time at LL.
Guys,several of you have misunderstood what GQ calls `fuel circles`.. more properly they are `fuel check circles`,,,
At the end of each `leg` of the navex ,in planning, a small circle,about 1" diam. is drawn,with a horizontal line across the circle.
In the top half of the circle is drawn the amount of `fuel remaining `expected`.
In the lower half of the circle(probably in `red`,is the `minimum fuel required` to complete the sortie,flying the rest of the route..
Therefore,at all times the fuel in the `top` segment should always be greater than in the lower half....Irrespective of whether you lean or not..
It is a simple `Howgozit`,so that one can check easily if fuel is sufficient.
For those that have drifted into `range circles`,fuel flowmeters and GPS,the OP is just learning his trade with the simple Grob... RTFQ..
At the end of each `leg` of the navex ,in planning, a small circle,about 1" diam. is drawn,with a horizontal line across the circle.
In the top half of the circle is drawn the amount of `fuel remaining `expected`.
In the lower half of the circle(probably in `red`,is the `minimum fuel required` to complete the sortie,flying the rest of the route..
Therefore,at all times the fuel in the `top` segment should always be greater than in the lower half....Irrespective of whether you lean or not..
It is a simple `Howgozit`,so that one can check easily if fuel is sufficient.
For those that have drifted into `range circles`,fuel flowmeters and GPS,the OP is just learning his trade with the simple Grob... RTFQ..
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I remember the civvie pilots at Shawbury getting an award for saving x amount of fuel simply by retracting the undercarriage on ccts. (For the unknowing Shawbury is where they used to hack around the cct all day in JP3's training newbie ATC chaps and chappesses.)
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Eureka!! Sycamore, you're brilliant!! Thank you for your post, that is PRECISELY what a fuel circle is....and the lower half of the circle (minimum fuel required) is indeed in red.
Thing...I thought the trainee wokka boys and girls were there to provide enough sport for the trainee air traffickers??!!
Thank you for your post, that is PRECISELY what a fuel circle is....and the lower half of the circle (minimum fuel required) is indeed in red.Thing...I thought the trainee wokka boys and girls were there to provide enough sport for the trainee air traffickers??!!