Comp Flt Pln: APU fuel and Taxi in fuel
 

Hi,

our company CFP doesn't have APU fuel nor Taxi in fuel,

we have only the Taxi out fuel which is defaulted at 200kg for the A320.

another question i would like to clarify is on the first sector est arrival fuel for example 7000kg, then the next sector fuel required will be again 7000kg.

so once we taxi in and use the APU for the transit, we are already short on fuel required by at least 200kg.

any suggestions?

some commanders are taking more fuel to account for this case.

our CFP total fuel consist of (trip fuel,cont 5%,altn,rsrv"30min",taxi"200kg" and extra).

the thing that it confusing me is the arrival fuel and the next sector departure fuel are the same !

thanks

The normal APU fuel is included in the taxi out. You should add some extra if you consider an use of APU that would exceed that "time".
The taxi-in is not considered in the minimum fuel requirements since your minimum legal fuel is from take-off to to landing.
The taxi-out fuel follows the same philosophy: it could make exceeding the max tow, providing at line up you have the fuel required to arrive at destination, plus reserves.

This is only an issue if you are tankering fuel as it sounds like you are talking about.
In this instance most people will look at the second or last sector "fuel required" then add the burn, taxi, and a little extra from the first/second/etc sectors. I don't know which CFP sytem you use so can't comment on its format.
Put simply, you can't depart on any sector with less than required fuel . First sector is no problem as you are way over, departing on the last sector with required fuel is the trick and experience will help you achieve this.
I don't see your problem.
Also, 200 kgs seems a little high for taxi fuel, we use just over half this.

If on transit, you find you are a little 'light' for fuel for the return, you can consider:
1- reduce taxi fuel to less than 200kgs
2- possibly chose a closer alternate to reduce diversion fuel
3- read your ops manual, but you should be able to specify a closer destination with your original destination as alternate. You do NOT have to specify on the flight plan you have done this. Inflight, 95% of the time, you will find fuel in hand to continue to your original destination. It is really just a paper exercise.
4. Is your final payload going to be lighter than the estimated payload used in the return fuel plan?

The aim is to not have to connect a bowser to fill up with just 300kgs fuel!

Further to what Rainboe posted;

We must carry 10% contingency for A-B fuel. It is permissable to depart without this so long as you arrive at a PNR with 10% contingency from PNR to destination.

For longer sectors where you pass suitable aerodromes along the way, this has obvious benefit.

waren, the OPS 1 (Jar or EU) requires 5% only, allowing to reduce it to 3% naming an ERA, or by using DDP (decision point procedure) or some other procedures I personally find quite complicated (the DDP is another one indeed, in the past it was much simpler).

What they should include, in my opinion when calculating the second sector fuel, is a sort of manouvering fuel to cover apu running during transit time.

I know. Australia has some very different ideas to the rest of the world about how aeroplanes should be flown.

Fuel requirements is but one example.

- yes, me too! Those 'some commanders' are absolutely right. Forget 'fudging' your figures a la Rainboe - your company needs to revise its PLOG system. If they will not, then the alternative is for 'some commanders' to uplift those 200kg every time on the turn-round - that will sort OPS out PDQ. Your PLOG should be issued LEGALLY and not rely on 'fudging' the figures to make it work.

Fuel figures are adjustable in the various computerised flight planning systems. There is a default which is specified for a fleet (or particular aircraft) and when you run a plan you can add extra for taxi, holding etc. which can make the plan more accurate according the airports involved and or weather conditions etc. If you are not getting what you want out of the system you should contact your flight planning provider for advice or help.

However you do it, sufficient fuel for the next sector is required.

This is only an issue if you are taking round trip fuel. The taxi in fuel is no where and does not need to be.
Minimum round trip fuel = minimum required for return sector 2 + adjusted sector (trip) fuel 1 (due increased ATOW perhaps) + taxi out & APU sector 1 + taxi in after sector 1 .
This calculation includes only 1 contingency fuel. To avoid any embarassment on turn round and having to ask for 200kgs to be minimum legal, it might be a good idea to plan to land with minimum return + a bit.
If you can make round trip with no problem then try for it. If it will be very close, then I prefer to land with 500-800kgs short of minimum return so there is no question you will uplift. Landing with minimum return - 1-200kgs is a real pain for everyone. Shall we shan't we?? Fudge the figures etc. This is especially true if the weather at sector 2 destination is not nice and you really wanted more than minimum, but you are 200kgs less than what you wanted.

Fudging is an art that comes with experience. We all have to fudge occasionally. Knowing how to fudge legally and sensibly is an acceptable part of the job. Official fudging occurs- how happy are we with official loadsheet standard weights of 88kg per male (including hand baggage), 70 kg per female, or charter standard baggage weights 13 kgs (European) or 15 kgs International? When I go skiing, I cannot get my baggage weight below 22kgs, and my ski jacket pockets in the cabin tend to hold rather heavy items as well! The whole of aviation is fudged at various times, and sometimes as an experienced aviator, you must fudge your way through the job, but safely! I would have thought anybody carrying roundtrip fuel would have uplifted a bit extra to cope with contingencies, especially when the return weather as a bit dodgy. It doesn't take academic analysis down to the last kilogram. If you are prohibited from doing so, then the company must expect small uplifts at the transit station. Often, carrying round trip fuel is impractical because of ground wing icing caused by cold fuel on the outbound leg, and you must plan to uplift with warm fuel.

The key to it all is intelligent pragmatism. We used to call it 'common sense', but everything seems to have to have complicated titles these days!

Forgive my simplicity, but isn't that why captains get the extra bucks? To look at the PLOGs, analyse them and then modify computer fuels to get the right amount of fuel to satisfy safety, legality and sense.

On how many airports do you need 200 kg taxi out fuel? I know just a couple of. Mostly you need the half of it. We have cpts changing taxi out fuel from 200 to 135 as it is of their "experience". Anyway in my opinion this leads to a strange sort of academic flying. Add a little more extra for reasons you feel unlucky with, thats it.

You cannot always assume 200kgs taxi out fuel. If you are planning a max take off mass, then if you burn less on taxi, you will officially be above max weight limitation. But if you are underfueled and you know you will burn less on taxi, then it is perfectly reasonable to specify any figure for taxi you may reasonably deem fit. It may help you avoid an unnecessary fuel uplift if you are down to minimum fuel. It's called 'fudging' again! Criticise me if you will, but accused of 'fudging' I put my hand up as 'guilty as charged!'. I have never once been criticised for it......apart from here on Pprune, by people who aren't sure of what they are talking about!

Our flight plans assume the least favourable departure and arrival will be flown, but aren't particularly generous with fuel otherwise. Captains regularly take more, particularly when carrying return fuel. Some routes always seem to need extra, where as a few others give you quite a bit more.

Experience helps with knowing when congestion occurs, where you will be held low, when track shortening can be expected etc.

On the 737 700 , fuel from start up until take off is 10kgs/min...hence 200kgs gives you 20 minutes.
If you take off with less than take off fuel (ie you burnt 300kgs due to delay while deicing for example) you ARENT legal to take off.
Yes you may save fuel enroute but it still doesnt make it legal,you may also change your alternate but a proper OFP must be calculated for proper fuel calculation( longest STAR...)

Thats my 2 cents.:8

Boingboingdriver
 

Don't really agree with you as contingency fuel would certainly cover the additional 100 kgs in your example. Contingency fuel can be used during taxy out if necessary.

If you had used all of your contingency during taxy out then you could consider nominating another (closer) destination and re-flightplanning in flight to see if you could legally continue to your original destination.


Regards
Exeng

I believe Contingency fuel ( 5% of trip fuel) is only to be used for IN FLIGHT re-planning purposes in case for example your initial alternate becomes unavailable..

My 3 cents...:cool:

But I believe we all agree that if missing 50-100kgs of fuel before takeoff , one may elect to go rather than delaying the flight.(knowing that enough fuel is available for the destination and possible alternate).
However a more detailed planning of fuel uplift will cover expected delays during taxi and avoid too many head scratching on the holding point..

My 4 cents:E

my 5 cents:
contingency should not cover before take-off discrepancies.
in my opinion the easier way is to calculate 2nd sector including all known fuel augmentations (e.g. extended use of APU, longer taxi, manouvering fuel etc...), then when you elaborate the "min fuel at destination" in 1st sector flight plan, you're safe with legal requirements for the next departure.
That's on the paper of course, should sector one burn more than planned and make a dent on 2nd sector fuel, well that brown stuff happens ;)