Fuel Planning in Civy Street

[BluntM8]

Hey Guys.

Just a question out of curiosity. A bit geeky too, but in my line of work fuel management is a big thing and I was curious about how much of what I do is similar to the guys operating civilian aircraft from bug-splatter to airliner.

In the RAF (my personal area is nav training) we make a big deal of fuel management. A big part of my work load is based around making sure we have the fuel to hit our targets, and considering the implications of any trends in fuel consumption. So my questions are:

Bingo Fuel - does anyone on Civy Street use the concept of Bingo Fuels (the min fuel required to rtb by the most efficient routing, plotted as rings at 50 nm intervals from base and at key points.) ??

Combat fuel? (- the difference between what I have in my tanks and the minimum fuel I need to complete the planned route. )And from that, the concept of negative and positive combat fuels?

What about getting airborne? We would normally only want to get airborne with full fuel, and getting airborne with negative combat will necessitate a fair amount of airborne re-planning. I've heard that airliners might get airborne with the minimum fuel required for the planned route (plus diversion) - what I'd call zero combat fuel - to take advantage of cheaper fuel prices worldwide. Does that happen or will you always take full fuel?

I would just love to know if the way I think about fuel is remotely related to how you guys do. It's been on my mind for a while, please - any light that can be shed will be gratefully received!

Blunty

[Rainboe]

Blunty- it's written up in ops manuals quite clearly. It takes the form of:
Trip Fuel to destination
Diversion Fuel from Go around to designated alternate
A Contingency reserve (usually 3% or 5% of the combined above total)
A Final Reserve to empty tanks not to drop below (30 minutes)
Taxy fuel is added on

Under what parameters you can reject an alternate and commit to Destination are also laid out in ops manuals.

Complications are long range routes, for instance ETOPs, where you must ensure at all stages you have enough fuel to divert to Diversion airfields en route, even in an engine failure/low level cruise case, and can always reach an airfield throughout flight- not always easy on extended overwater trips. Across the Atlantic in twins, we always have to have either the Azores or Iceland available to us.

Carrying extra load costs 3-4% of that load in fuel/hour. Therefore a 10 hour flight carrying 6000kgs extra fuel could use up over 2000kgs of it. We have to be economically minded- it is a trade-off: is it better to carry say 2000kgs extra on average every flight or try and not carry extra fuel if you feel you can, and very rarely have to divert to Aternate because you have not carried it? It is regarded as not, and the pressure is to minimise extra fuel loads.

Your 'Combat Fuel' is simply any extra fuel we have above the minimums specified above to complete the flight. We call it 'extra', and we might have onloaded it to allow for holding at Heathrow or restricted altitudes en route, or 'bad weather at destination' comfort, or even ended up not using as much as planned.

We used to carry round trip fuel for shorter trips or multi-leg flights. Now the tendency is to try and not do so. But, I recently did a flight (3 hours) to a Greek island where a table told us that fuel was 114% of the cost at Gatwick. So one tends to be a bit more liberal with fuel onloads out and try hard to minimise them back. But rtb is not really a consideration- we always stop where we're going!

On long range flights, it is rare, but you may not be able to carry fuel you need to Destination for weight reasons. There are legal fudges to declare your flight to a suitable en route point, then once inflight hoping that you are a bit ahead on fuel and can fudge the figures to legally inflight give you enough required reserves to destination. Very complicated....and people think we play cards and listen to iPods! It may happen you cannot legally complete the flight, and extremely rarely you may have to make a technical stop en route and land and take on more fuel. An additional hazard in that case is that invariably a pprune reader is just itching to paste it all over Rumours and News that 'you didn't have enough fuel for the flight and you had to do an emergency landing!!!!!!'. And someone else will interject with how shocking your airline was for going with not enough fuel and the pilots should be canned because he'd never do that in his flight sim! And so it goes on......

[411A]

Well said, Rainboe.:ok:

[BOAC]

Blunt - you may wish to take a look at JAROPS1 in JAROPS (http://www.jaa.nl/operations/public_area.html) which govern Euro commercial ops - section JAR-OPS 1.255 (currently on page 1-D-5).

As Rainboe says, we normally land 'away' from base, but in my day Bingo often related to either a destination or alternate airfield, so in that respect we are not that different. As you see, in simple terms we normally 'plan' to arrive at touchdown at destination with diversion fuel + sub para c-3-ii and iii and 'expect' to arrive with c-3-i and normally with c-3-iv and c-4. It is some time since I engaged in 'combat' outside the military:) and we have no concept of a 'joker' fuel either. I suppose our 'combat' take place with ATC routings/delays/levels and inaccurate planning winds.

[MANAGP]

Blunty

Reading JAR ops and the company ops manual is the best source of info. I find nothing nore annoying about hearing phrases such as Bingo fuel etc from the RH seat. Ex military folk have to accept that they aren't in the mob anymore and using non standard expressions can lead to confusion.
A recent conversation is a good example, I was asked what are we going to do if the runway is black? I pointed out that I'm not really prejudiced towards any particular colour but that I typicaly find the tarmac runways are black. I received a very puzzled look from the RH seat!

[BOAC]

MANAGP - the best answer is to hide one of this flying gloves when he is not wearing them.:)