Fuel Q
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Fuel Q
Just a quick question for the boffins
Had a rather large ZFW drop on the last LH and made the appropriate corrections. (Another CFP was out of the question)
I was wondering if after the correction our CRIT PT fuel serves we're still intact? Is this always the case if I apply the right correction or can we be left short?
Cheers
Had a rather large ZFW drop on the last LH and made the appropriate corrections. (Another CFP was out of the question)
I was wondering if after the correction our CRIT PT fuel serves we're still intact? Is this always the case if I apply the right correction or can we be left short?
Cheers
The answer is yes, the required fuel reserves will always be intact, even if the corrected fuel required drops below the figure shown on the depress ERA analysis on the CFP.
The Line Ops page on the Flight Crew part of IntraCX (under 'Guidelines & Policies') has the answer to this and many other questions.
The Line Ops page on the Flight Crew part of IntraCX (under 'Guidelines & Policies') has the answer to this and many other questions.
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Upon recalculation of the fuel after a ZFW drop your crit points are still good.
If after dispatch you are going to be less than required at the crit point after doing your own calculation are you going to divert or keep going?
Once in the air surely it does not really matter, you do what is required and often the airports used in the calculations are totally crazy. Who cares if you have fuel to fly over two suitable airports on the way to your crit point ERA after a depress.
If its good at the planning stage then really thats all you need.
Bet your an Aussie :-)
If after dispatch you are going to be less than required at the crit point after doing your own calculation are you going to divert or keep going?
Once in the air surely it does not really matter, you do what is required and often the airports used in the calculations are totally crazy. Who cares if you have fuel to fly over two suitable airports on the way to your crit point ERA after a depress.
If its good at the planning stage then really thats all you need.
Bet your an Aussie :-)
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Although FLt Ops say the CFP corrections are good for Mandatory fuel, a few years back had a large 0FW drop and did the correction and established a new Final Req'd. Dispatch ran a new plan and the new plan had 300kgs more as Fuel Req'd. We were probably OK because of the 5% extra built into the mandatory, but I am now cautious about using the corrections on large 0FW drops on long sectors.
Sloppy Joe, as for what to do after airborne, I think you need to talk to a training god. Perhaps also ask him about the difference between "your" and "you're"
Sloppy Joe, as for what to do after airborne, I think you need to talk to a training god. Perhaps also ask him about the difference between "your" and "you're"
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Threads like these prove what a bunch of wankers we have at CX. You guys would rather haggle over a few hundred kilograms of fuel and grammar than discuss real issues like SHP. We surely make the third floor's job easy by putting our effort into the dumbest topics. What would you like to discuss next? My favorite color?
Last edited by cxorcist; 5th May 2013 at 16:12.
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To Answer the Question
A very good approximation of the new CP fuel required is found by taking a ration ratio of the new CFP total fuel/Old CFP total fuel and multiply this by the old CP fuel. This will be within a couple hundred kilos. Use the same mandatory if you had it as the change in it will be very small. You can use the same ratio to find what the fuel required at each point is. We used to use this all the time before the days of the FMC.
You can always then ask for a new cfp enroute to backup your math.
(some w@nker will probably point out that a better ratio can be found by leaving the contingency fuel out of the equation, and they would be correct, but the difference is negligible)
You can always then ask for a new cfp enroute to backup your math.
(some w@nker will probably point out that a better ratio can be found by leaving the contingency fuel out of the equation, and they would be correct, but the difference is negligible)
Last edited by bellcrank88; 8th May 2013 at 15:08.
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I'd like to point out that better ratio can be found by leaving the contingency fuel out of the equation. (but the difference is negligible.) And i am friends with that w@nker...
Last edited by channis; 9th May 2013 at 09:40.
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Don't use the old and final CFP fuel in the equation. Instead, divide the new burn off figure by the old burn off figure and then use this value to multiply against any fuel figure on the CFP to get the updated fuel burn off.
Last edited by raven11; 9th May 2013 at 11:55.
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Mmmm
Just spoke to a guy who had the ZFW drop just under 9T going to the west coast of the US, did the correction to the trip fuel/total fuel double check by requesting a new flight pan.
MAND went up 500kg!
New plan showed they were now 1.3T below the legal departure fuel based on their LNDG CORR.
Perhaps CX should say ZFW changes up to "X amount" are acceptable.
Just spoke to a guy who had the ZFW drop just under 9T going to the west coast of the US, did the correction to the trip fuel/total fuel double check by requesting a new flight pan.
MAND went up 500kg!
New plan showed they were now 1.3T below the legal departure fuel based on their LNDG CORR.
Perhaps CX should say ZFW changes up to "X amount" are acceptable.