Ok guys, looks like I need to clarify a few things...! Have just spent the morning at the Club as it happens and as gusts of 40kts meant that flying was out, we have been chatting Navexes and Sector Recces (hmmm, i'm sure that one will get you all going too
) which we'll fly next time.
Broomstick - many thanks for your thoughts. I will certainly ask around at work as I know there is at least one Herc pilot. We also have ex-E3-D pilots on Station and a good friend of mine is ex-Vc10s so there are plenty of the Multi drivers around to ask! So in your opinion then, why are fuel management circles not good for legs of more than 50nm? I would ahev thought thaat, so long as all the figures were accurate, any length of leg was OK. The Grob is a twin seater with very little luggage space, so quite light really
Even in a small aeroplane I allow for taxi fuel and I do calculate my fuel from destination to alternate (just in case the aircraft ahead of me does a wheels-up landing on the only runway at my destination). I plan each leg of a multi-stage trip as though each was a separate trip.
Div fuel, this was one of the things I was discussing with my QFI today. The circles show planned fuel at all points. Div Fuel is red fuel and in our case we need to RTB with 18 litres FOG, 20 litres Div fuel (to get us easily to the other two local RAF airfields). Therefore the red fuel on the last point needs to be a minimum of 38 litres.
I don't have an issue with somebody doing fuel planning one way or another way, so long as it is realistic for the situation. (The "fuel circles" method is not good for "slow GA" because the wind is likely to be very significant, so the circles are not circles anyway).
Peter, as other have said, these are indeed not range circles, but a quick and simple way of seeing roughly how much fuel you expect to have and therefore whether you need to divert.
pick up a tailwind on leg 1 you might then find your RTB fuel was no longer sufficient when you turn around to fight the headwind. I think we need to check back with GQ whether the fuel calculation allows for wind figures and Groundspeed?
As to the wind...well, asked my QFI that too and the answer was straightforward...its not an issue because you will even out fuel useage during the navex...ie on the southward leg we may have a tailwind...therefore use less fuel...so use more fuel on northward leg back home due to the headwind but we have more anyway because we used less than calculated because of the tailwind on the outward leg - seems logical to me! Groundspeed? I'll have to ask about that one!
Bad wx Divs? very true GW, we don't fly in bad wx..todays a case in point
But true, we could end up in bad wx, thats where common sense and training come in. If I was solo, saw a massive great CuNim in my way I would see where I could divert to with the fuel I had, or decide maybe if its just one cell I could skirt round it..surely flying is all down to common sense, training and the pilot deciding the best course of action for a situation with div, fuel, wx all taken into consideration! Also, take Maorigh's point about ice...Last Weekend was a lovely winters day and we were flying...but were still concerned about ice!
Well, better get on with my navex planning with fuel circles to Wyton
GQ