Originally Posted by
Grob Queen
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!
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.........