A320 Load factor protection
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A320 Load factor protection
Does any one know where does the load factor value comes from for the load factor protection. Is it a IRS feed or a predictive computation from the FAC based on other parameters ?. The FCOM does not say.
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Power supply is provided thru "respective" computer : ACCLRM #1 from ELAC 1,ACCLRM #2 from SEC 1, ACCLRM #3 from ELAC 2, ACCLRM #4 from SEC 2. Single accelerometer fault causes only class 2 maintenace message, F/CTL will be displayed as STATUS for pilots. Btw. if ELAC 1, SEC 1 or 2 is deactivated as per MEL, due to power supply you lose one accelerometer too. If more than one acclrm. fails, aircraft switch to ALTERNATE or DIRECT law. FCOM probably does not cover description so deep. Just schematic in DSC 27-10-20 shows accelerometers input to ELACs. I am sorry, whole logic is not really so simple as I was able describe here from my memory.
Last edited by LEVEL600; 20th Jan 2015 at 18:35.
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LEVEL 600 you know your stuff!
I have a question:
The load factor limit is based on the maximum loads, which are calculated for MTOW. So if the MTOW is 77 tons and in clean config the g limit is 2.5 gs, the maximum load is 77x2.5 tons right?
So if you are in approach to destination after a ferry flight and your GW is only 45 tons, you can only pull 2.5, with is much less load (45x2.5 tons).
So this "full authority" that Airbus boasts about in case of a GPWS is not so full, I guess, because if in that approach you would survive with a 77x2.5 ton pull up to avoid a mountain, but not with a 45x2.5 ton one… Well, someone could go to the lawyers and sue Airbus for a lot of millions
I have a question:
The load factor limit is based on the maximum loads, which are calculated for MTOW. So if the MTOW is 77 tons and in clean config the g limit is 2.5 gs, the maximum load is 77x2.5 tons right?
So if you are in approach to destination after a ferry flight and your GW is only 45 tons, you can only pull 2.5, with is much less load (45x2.5 tons).
So this "full authority" that Airbus boasts about in case of a GPWS is not so full, I guess, because if in that approach you would survive with a 77x2.5 ton pull up to avoid a mountain, but not with a 45x2.5 ton one… Well, someone could go to the lawyers and sue Airbus for a lot of millions
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Doesn't work like that. Load factor is effectively a force proportional to the weight. Just because the wings don't fall off doesn't mean you can exceed 2.5G on the rest of the structure (think cargo hold flooring etc).
Not sure what you're trying to prove re GPWS performance but you're completely wrong. Nominally the light and heavy aircraft will achieve the same acceleration in the pitch axis but the flight path change in the lighter aircraft will be faster.
Not sure what you're trying to prove re GPWS performance but you're completely wrong. Nominally the light and heavy aircraft will achieve the same acceleration in the pitch axis but the flight path change in the lighter aircraft will be faster.
Only fuel taken from the Center tank would theoretically allow you to pull a little bit higher g without overloading the Center wing structure.
Still, even in that case the objections by @Fursty Ferret are valid.
Anyway if 2,6g instead of 2,5g would have saved the day I would consider that really, really unlucky. I don't remember a single case in aviation history where such a difference in allowable g would have made a difference....
Last edited by henra; 24th Jan 2015 at 13:44.
More altitude and thus more Speed at the time of recovery would have made a difference.
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Fursty Ferret wrote:
Doesn't work like that. Load factor is effectively a force proportional to the weight. Just because the wings don't fall off doesn't mean you can exceed 2.5G on the rest of the structure (think cargo hold flooring etc).
Not sure what you're trying to prove re GPWS performance but you're completely wrong. Nominally the light and heavy aircraft will achieve the same acceleration in the pitch axis but the flight path change in the lighter aircraft will be faster.
Doesn't work like that. Load factor is effectively a force proportional to the weight. Just because the wings don't fall off doesn't mean you can exceed 2.5G on the rest of the structure (think cargo hold flooring etc).
Not sure what you're trying to prove re GPWS performance but you're completely wrong. Nominally the light and heavy aircraft will achieve the same acceleration in the pitch axis but the flight path change in the lighter aircraft will be faster.
Actually, the limit load of an airplane is not measured in Gs, but in force (kilos or newtons or whatever). Then, certification requires that the airplane has to be able to withstand a given load factor at the certified MTOW. However, at less weights you need more Gs to have that same limit load.
Originally Posted by CONFiture
Maybe in Perpignan pulling some extra G could have saved the day ...
Originally Posted by Microburst2002
Actually, the limit load of an airplane is not measured in Gs, but in force (kilos or newtons or whatever).
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Originally Posted by Clandestino
How many Gs one needs to pull up from 50° nose down at 1200 ft doin' 180kt. Say, what is A320 Vs1g in clean config at 53.7t?
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Clandestino, 2.5 g is a limitation you see in the FCOMs, but the limit load is just that: a load. If you don't exceed it you don't have any structural concerns.
At MTOW, you will reach that limit load if you pull 2.5 g. At lower weights you don't reach it with 2.5 g. It takes more g. that is why I say that in a GPWS scenario, you might require any extra g load available due to your weight being low.
At MTOW, you will reach that limit load if you pull 2.5 g. At lower weights you don't reach it with 2.5 g. It takes more g. that is why I say that in a GPWS scenario, you might require any extra g load available due to your weight being low.
