A320 fuel penalty
Hey guys I have a question about fuel penalty of Aileron. In the case of ELAC 1 or 2 or 1+2 fault, ECAM says that we need to apply fuel penalty factor table. And explanation is FUEL CONSUMPT INCRSD appears when the failure (or combination of failures) affects the nominal aerodynamic characteristics of the aircraft. But FCOM says that if Aileron fails, then damping mode will active. Damping mode doesn’t make any fuel penalty. Is that right? And if it is correct, the penalty factor table is used only in the case of damping mode doesn’t work correctly. Then if airbus consider that case, why there are no fuel penalty table for Elevator? I feel little bit contradiction and I thought I misunderstanding something. Thanks |
Originally Posted by TTT0521
(Post 10578205)
Hey guys I have a question about fuel penalty of Aileron. In the case of ELAC 1 or 2 or 1+2 fault, ECAM says that we need to apply fuel penalty factor table. And explanation is FUEL CONSUMPT INCRSD appears when the failure (or combination of failures) affects the nominal aerodynamic characteristics of the aircraft. But FCOM says that if Aileron fails, then damping mode will active. Damping mode doesn’t make any fuel penalty. Is that right? And if it is correct, the penalty factor table is used only in the case of damping mode doesn’t work correctly. Then if airbus consider that case, why there are no fuel penalty table for Elevator? I feel little bit contradiction and I thought I misunderstanding something. Thanks |
Hello everyone,
I would like to know if you can give me an example of how to calculate the Fuel Penalty Factor in the A320 with a landing gear failure that is 180%. I know how to calculate the Trip fuel penalty, but I don't know where to apply or add that result to know what my real fuel would be at landing. Would an example with numbers be possible? Thank you |
FOB = 9 tons
EFOB at destination in FMGC = 3 tons Therefore, trip fuel is 6 tons, 6 x 1.8 = 10.8 tons actual trip fuel with landing gear failure. I honestly hope it goes like this because this is how I have been explaining it to my trainees for years now... |
Thanks for the reply.
And when would you declare Minimum fuel, that is, knowing your new trip fuel, how do you calculate the minimum diversion, which is the sum of the final reserve and alternative? |
Originally Posted by iggy
(Post 11385053)
FOB = 9 tons
EFOB at destination in FMGC = 3 tons Therefore, trip fuel is 6 tons, 6 x 1.8 = 10.8 tons actual trip fuel with landing gear failure. I honestly hope it goes like this because this is how I have been explaining it to my trainees for years now... |
Originally Posted by KingAir1978
(Post 11385213)
This calculation is not correct, I'm afraid. The PENALTY is 180%. Therefore the total fuel used would be the fuel normally used PLUS the penalty. You have only calculated the penalty (6x1.8 = 10.8) The total fuel burn would thus be the 6 tonnes, PLUS the 10.8. = 16.8 tonnes. Also you may need to include the penalty for open gear doors of 15%. To be conservative just multiply the fuel-burn by 3.
|
Without wanting to drift too much, I've been given a rule of thumb that with gear stuck down, the first 2 digits of your FOB is how many minutes until tank's are dry.
eg FOB 2800kg = 28 minutes until tank's are dry. Hopefully never have to find out if its true! |
Originally Posted by thetimesreader84
(Post 11385676)
Without wanting to drift too much, I've been given a rule of thumb that with gear stuck down, the first 2 digits of your FOB is how many minutes until tank's are dry.
eg FOB 2800kg = 28 minutes until tank's are dry. Hopefully never have to find out if its true! |
Try this for an example of what can go wrong.
Hapag Lloyd A310 at Vienna July 12 2000. |
Originally Posted by KingAir1978
(Post 11385213)
This calculation is not correct, I'm afraid. The PENALTY is 180%. Therefore the total fuel used would be the fuel normally used PLUS the penalty. You have only calculated the penalty (6x1.8 = 10.8) The total fuel burn would thus be the 6 tonnes, PLUS the 10.8. = 16.8 tonnes. Also you may need to include the penalty for open gear doors of 15%. To be conservative just multiply the fuel-burn by 3.
|
Originally Posted by iggy
(Post 11385053)
FOB = 9 tons
EFOB at destination in FMGC = 3 tons Therefore, trip fuel is 6 tons, 6 x 1.8 = 10.8 tons actual trip fuel with landing gear failure. I honestly hope it goes like this because this is how I have been explaining it to my trainees for years now...
Originally Posted by KingAir1978
(Post 11385213)
This calculation is not correct, I'm afraid. The PENALTY is 180%. Therefore the total fuel used would be the fuel normally used PLUS the penalty. You have only calculated the penalty (6x1.8 = 10.8) The total fuel burn would thus be the 6 tonnes, PLUS the 10.8. = 16.8 tonnes. Also you may need to include the penalty for open gear doors of 15%. To be conservative just multiply the fuel-burn by 3.
So which one is it? May someone explain with another example perhaps? |
Originally Posted by k.swiss
(Post 11385754)
Interesting..
Very interesting.. So which one is it? May someone explain with another example perhaps? |
[penalty +30%] >>> FMS burn (100%) + 30% = 130% = 1.3 x FMS
[penalty +180%] >>> FMS burn (100%) + 180% = 280% = 2.8 x FMS Don't forget the additional +15% for doors ajar in case of gravity extension. |
Since penalty factor of 180% is huge so the calculation is creating some confusion. Let's take FOB 6000kgs and EFOB 4000kgs. That gives burnoff of 2000kgs. Take a penalty factor of say 15%. When applied to 2000kgs will give 300kgs. Surely that can't be the BO with failure but only additional fuel required. It will be added to normal burnoff of 2000kgs giving the figure off 2300kgs as the trip fuel with failure. So the new EFOB with FPF will be
6000-2300=3700kgs.This should make it clear. |
Looking at an old Safety First magazine Kingair1978 is correct.
|
Originally Posted by vilas
(Post 11385769)
Since penalty factor of 180% is huge so the calculation is creating some confusion. Let's take FOB 6000kgs and EFOB 4000kgs. That gives burnoff of 2000kgs. Take a penalty factor of say 15%. When applied to 2000kgs will give 300kgs. Surely that can't be the BO with failure but only additional fuel required. It will be added to normal burnoff of 2000kgs giving the figure off 2300kgs as the trip fuel with failure. So the new EFOB with FPF will be
6000-2300=3700kgs.This should make it clear. First question, is the penalty not also applied to alternate/final reserve fuel incase of GA? Second, to summarize if at any point the EFOB (with penalty) goes below the actual EFOB on the MCDU then we can not continue and better to divert as fuel will not be enough given the penalty?
Originally Posted by FlightDetent
(Post 11385763)
[penalty +30%] >>> FMS burn (100%) + 30% = 130% = 1.3 x FMS
[penalty +180%] >>> FMS burn (100%) + 180% = 280% = 2.8 x FMS Don't forget the additional +15% for doors ajar in case of gravity extension. |
Originally Posted by KingAir1978
(Post 11385213)
This calculation is not correct, I'm afraid. The PENALTY is 180%. Therefore the total fuel used would be the fuel normally used PLUS the penalty. You have only calculated the penalty (6x1.8 = 10.8) The total fuel burn would thus be the 6 tonnes, PLUS the 10.8. = 16.8 tonnes. Also you may need to include the penalty for open gear doors of 15%. To be conservative just multiply the fuel-burn by 3.
The two key points to look for this question are: https://cimg3.ibsrv.net/gimg/pprune....4a1597442.jpeg How to calculate Additional Fuel https://cimg0.ibsrv.net/gimg/pprune....62f5fd927.jpeg Additional fuel must be added to the fuel prediction calculated by the FMS. I repeat: it is scary to think the amount of pilots that are going to run out of fuel in the air after I taught them the wrong way. And, totally unrelated to this thread, but worth mentioning: I got the answer to this from the nerdy, sweet, glasses-wearing, non-aviation related, amazingly intelligent, humorous, incredibly hot and with magic eyes, love of my life. It took her less than 5 minutes to come with a well documented answer, even though the closest she has been to an airplane has been as a passenger. And on top of that, her nickname is an acronym that we pilots use on a daily basis, can't ask for more! So, this is to you, I know you are going to love it. Happy belated Saint Valentine! |
Originally Posted by iggy
(Post 11385990)
I repeat: it is scary to think the amount of pilots that are going to run out of fuel in the air after I taught them the wrong way.
You did not teach them to use 15% instead of 115% for the smaller failures (a.k.a. 85 less fuel). Forgetting about the baseline 100 in the l/g down case is a widespread error, but a well identified one. Re-assimilation in progress for many years. If you missed the moment to point this visual trap, it's a lost opportunity, no worse. Sure as hell the 180+15 look bad enough already. :E |
Originally Posted by FlightDetent
(Post 11385998)
Perhaps I am missing the sarcasm.
You did not teach them to use 15% instead of 115% for the smaller failures (a.k.a. 85 less fuel). Forgetting about the baseline 100 in the l/g down case is a widespread error, but a well identified one. Re-assimilation in progress for many years. If you missed the moment to point this visual trap, it's a lost opportunity, no worse. Sure as hell the 180+15 look bad enough already. :E |
All times are GMT. The time now is 03:28. |
Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.