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GW/ZFW/FOB Incorrect value(s)


TheFl4me

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The Value(s) indicated on the A330 MCDU, SD and E/WD make no sense.

 

FOB = 4800kg

GW =  175000kg

indicated ZFW = 161500kg

 

GW - FOB = ZFW right? not in this case.

 

175000kg - 4800kg = 170200kg

 

170200 - 161500 = 8700kg

 

So the actual ZFW appears to be 8700kg heavier than the one i set upon loading the aircraft?

No wonder I am arriving at my destination with 4t less fuel than predicted (10h flight).

 

Am I missing something here?


EDIT: Aerosoft A330 v1.0.0.6 and whatever the latest P3D4 v4.5 build is.

 

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  • Deputy Sheriffs
  • First something seems to be wrong with the figures on the left side of the menu e.g. the ones to be used for for boarding/Loading - because INIT LOADSHEET is marked red (normally means no Loadsheet avaibale). Did you use the fuelplanner and then INIT LOADSHEET to get the figures into the menu or did you manually enter those? 
  • Second those are quite unrealistic e. g. 300 pax and only 0.900 MT for all the baggage?

I used your figures and entered those into the Fuelplanner (see attached screenshot). Then I loaded the A330 in the TA state and used INIT LOADSHEET and the correct values from the FUELPLANNER were inserted. The same happens if after loading the A330 in the TA state I manually enter those values into the left side of the LOAD menu.

The next step then would be to load those values into the plane. You can use GSX, LSK1-3R or LOAD INSTANT LSK4R. Because of the much too low cargo weight the status for CARGO will be blinking green - there is a minimum based on the number of passengers. Therefore I changed the CARGO to 10.00 MT. 

Based on this the LOAD menu displayed a calculated corrected ZFW of 162.5.

After engine start I checked those values: ZFW 162.5 plus actual fuel of 63.3 (after engine start) = 225.8 and this is exactly the GW displayed on the LOWER ECAM.

So everything is OK and correct. I believe the problem is your handling of the MCDU3 LOAD MENU...... Please retry as stated above.

 

Regards,

Rolf

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Hello @Hanse,

 

I use simbrief as a flight planning tool, or rather I only use it as a fuel/perf calculation tool since I make the routes fully manually (eurocontrol validated etc...).

 

As with every other aircraft, upon loading it into the sim I enter the numbers from my OFP into the MCDU directly.

 

Based on my experience over the past years, I have come to the conclusion that simbrief includes the checked luggage from a passenger into the weight per pax value. (After doing some calculations it would seem that simbrief assumes the weight of 1 pax = 100-120kg), which explains why it then spits out such a low value for actual cargo since it already included it in the pax weight (wether this is the correct way to do this is up for debate, but fact of the matter is this is how it is currently calculated). 

I accounted for this my adjsuting the pax weight in the setup page on the MCDU.

 

I do not use the Aerosoft fuel planner because I find it to be severely innacurate in terms of actual fuel calculation. (Take your screenshot for instance, it is suggesting 48t of fuel for a flight which yesterday required almost 60t, 55t if the aicraft had had the correct ZFW). Or for the flight im doing today it suggested 20t less fuel than simbrief did (I triple checked the wind value altn distance etc...).

Its also missing some key data input values to estimate the fuel such as cost index and step climbs.

I have attached yesterdays OFP of that flight in this post incase you're interested.

 

Back to the problem at hand:

 

The loadsheet is marked red because after noticing the problem (in the last hour of the flight) I tried to fiddle around with the mcdu. and since I never used the fuel planner it had no data to import.

 

I started a flight after reading your post and indeed the problem for the incorrect ZFW seemed to have been the too low cargo value. I assume the MCDU didnt input the new value and kept the whatever the actual cargo weight was upon starting the sim (although it never blinked green yesterday). 

 

I have several problems with this though:

  1. I cannot comprehend why one would add a minimum cargo value? This imo is just asking for problems to happen...
  2. If there is a minimum cargo value, then entering a value below that should not be possible, and should instead be met with an error message such as "out of range" or something to avoid all this confusion.
  3. Why is it not an option to directly enter the ZFW/CG like in every other aircraft? Why all this jumping around? Dont get me wrong It might be a nice feature for some people, but it should not be the only way of being able to load the aircraft.

Kind Regards,

 

- Tristan

 

 

EDDFKSEA_PDF_06Jan20.pdf

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  • Deputy Sheriffs

Hi Tristan,

 

First, you are absolutely right that currently the FUELPLANNER has a bug calculating fuel. But this already has been fixed and the update will be included in the next experimental update. If I use this new version I get a value of 62.918 kg (based on your data) and this is nearly the same SIMBRIEF calculated for your flight (please see screenshot attached).

 

Second the general demand (and that is also our target) is to make the plane as much as real as it gets. But this includes not only the technic / features but also the procedures. So what about CG / Pitch Trim in your currently used procedure to set up the plane? Where do you get those values from - because SimBrief does not provide these values?

 

Third and this is the reason why we do not use just the ZFW value for loading the aircraft is that the splitting of pax and cargo has an impact on the CG of the aircraft. Also the max. pax numbers varies between the airlines - the A330 D-AIKO you were using for your flight carries a max. of 255 passengers. In addition to that the splitting is necessary if GSX is used for boarding pax and loading cargo.

 

Because you wrote that you do not use SimBrief for route planning I believe that there is no reason (after updating the fuelplanner) to use it anymore. Just make your settings in the fuelplanner and generate the loadsheet. Load this loadsheet into the MCDU (including CG/Trim) and everything is fine. With just one click then those values also will be transferred in the MCDU INIT B page - and all your settings are correct.

 

For people using SimBrief also for route planning: Take the ZFW from the OFP and adjust the fuelplanner sliders accordingly so that the ZFW from SimBrief is met. If the estimated fuel from SimBrief should be used just overwrite the TOTAL weight value. Then "Generate Loadsheet" and the remaining procedure is the same like mentioned above.  

 

Regards,

Rolf

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Hi @Hanse,

 

Thank you for your reply.

 

It is good to know that this is infact a bug with the fuel planner, however it is imo still of no use to me since it does not consider the Cost Index. (Estimating the fuel consumption based on distance, winds and  ALT is nice and all, however not considering the actual speed or rather thrust setting will make the prediction severly inaccurate (we both know there can be up to a 5t fuel difference between the lowest and highest cost index).

 

You are correct about the fact that simbrief does not calculate the CG. Here is my suggestion which other aircraft developers seems to do:

 

Lets take FSLabs as an example (because they are the only other good airbus developer and fully integrated GSX). When loading my fslabs I can choose to either enter a ZFW value, which if I do fslabs will then (I assume) randomize the pax/cargo ratio to fit that ZFW, and thereby also calulcate the TOW and ZFW CG. I (and fslabs) realize that this solution is liked but also disliked by many, so they ALSO offer the alternative option of manually setting the pax numbers and cargo weight. Now obviously once the CG has been calculated the takeoff trim can be seen by simply looking at the trim wheel and seeing what setting matches which CG.

 

The point is that they offer both options. 

Personally, I do not care how many pax/cargo I have as long as my actual ZFW matches the ZFW on my OFP, but I fully understand that this opinion is not shared by everybody.

 

What you explained (adjusting the sliders to get my ZFW) is what I am doing at this point, however I still would rather have the option that the system does this for me.

I think I didn't explain myself properly when talking about simbrief, I still very much need simbrief. The only feature I do not use it for is the auto-generate route feature. Every other feature (such as generating an OFP, Cost index based on WX and approx flight time, ETOPS, NOTAMS etc....) I still of great value to me and obviously not something that can be replaced so easily.

 

Regards,

Tristan

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  • Deputy Sheriffs

Hi Tristan,

 

You are comparing us with another competitor and one or two features they offer in a different plane. But what about also comparing the price and the features we included in the A330 like EFB, CFD, the automatic Checklist- with the Copilot-function or ViewFocus? And what do you mean by fully integrated GSX? The only difference I know is that you can use the MCDU line keys in their smaller models to start the GSX-functions whereas we use the MCDU3 line keys for the MCDU3 internal load function only. The reason is quite simple that they use the hotkeys from the GSX menu whereas those keys in the Aerosoft A330 are already used by another functionality like the checklist, which they do not offer!

 

Regards,

Rolf 

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Hi @Hanse,

 

My point was not to compare Aerosoft to Fslabs, or insinuate that one is better than the other in any way.

 

I was simply citing Fslabs as a proof of concept  for a feature that I believe should be implemented into the aerosoft a330 (directly entering the ZFW). I could have just as well cited the quality wings 787 as an example (similar price range and quality to the 330, they too allow the user to enter the ZFW weight directly.


I chose to use Fslabs as an example, not because of the price range or quality of the product, but because it has many similarities with your product (Airbus aircraft, similar loading process with both you and fslabs utilizing GSX etc...).

 

I dont think that this is too much to ask for a product of this price range (or did I misunderstand your previous message?). And it is definitely possible since multiple other developers (not just products with a price range of >100€) offer this aswell, so its less of a question of being able to, but rather more of a question being willing too..

 

Basically it all boils down to one question.

Is aerosoft willing to add a feature to enter the zfw directly as a alternative loading option to the current loading process?

Regards,

Tristan

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6 hours ago, Hanse said:

But what about also comparing the price and the features we included in the A330 like EFB, CFD, the automatic Checklist- with the Copilot-function or ViewFocus?

 

Personally, I did not purchase the A330 for any of these features, and in fact have not used any of them at all.

 

10 hours ago, Hanse said:

 If the estimated fuel from SimBrief should be used just overwrite the TOTAL weight value. Then "Generate Loadsheet" and the remaining procedure is the same like mentioned above. 

 

This doesn't currently update the CG and trim correctly, you need to fiddle with the fuel sliders to make your fuel match otherwise your balance will be out, see https://forum.aerosoft.com/index.php?/topic/149826-a3xx-fuel-planner-balance-update/

 

I too would like the function of being able to enter only a ZFW.

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  • Deputy Sheriffs
On 8.1.2020 at 22:30, Sharkbait sagte:

This doesn't currently update the CG and trim correctly, you need to fiddle with the fuel sliders to make your fuel match otherwise your balance will be out,

 

Those values are based on ZFW and used for the MCDU INIT B page resp. MCDU PERF TO page. Do not mix it up with the GWCG which includes the fuel and is automatically calculated / displayed on the upper ECAM display after engines have been started. 

So the procedure I suggested:

  • Use the sliders of the fuel planner until the ZFW is met with the one you got from SimBrief OFP
  • Overwrite the TOTAL fuel amount in the fuel planner
  • Generate Loadsheet
  • MCDU3 "Init Loadsheet"
  • Load the numbers into the plane using GSX, LSK1-3R or INSTANT LOAD LSK4R

is quite simple and working well. The values for ZFW as well as ZFWCG can be "transferred" into the MCDU  INIT B page by just double clicking the resp. LSK R. The Trim value automatically is transferred into the MCDU PERF TO page.......

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6 hours ago, Hanse said:

 

Those values are based on ZFW and used for the MCDU INIT B page resp. MCDU PERF TO page. Do not mix it up with the GWCG which includes the fuel and is automatically calculated / displayed on the upper ECAM display after engines have been started. 

So the procedure I suggested:

  • Use the sliders of the fuel planner until the ZFW is met with the one you got from SimBrief OFP
  • Overwrite the TOTAL fuel amount in the fuel planner
  • Generate Loadsheet
  • MCDU3 "Init Loadsheet"
  • Load the numbers into the plane using GSX, LSK1-3R or INSTANT LOAD LSK4R

is quite simple and working well. The values for ZFW as well as ZFWCG can be "transferred" into the MCDU  INIT B page by just double clicking the resp. LSK R. The Trim value automatically is transferred into the MCDU PERF TO page.......

 

I have not mixed it up with GWCG. The takeoff trim value is based off of the TOWCG, not the ZFWCG.

 

I've followed your procedure to show show where the error. You can't just enter the TOTAL fuel and be done with it. It requires deliberate manipulation of the fuel data (per https://forum.aerosoft.com/index.php?/topic/149826-a3xx-fuel-planner-balance-update/) in order to get a correct trim data for your TOWCG. I believe this further highlights the desire to either:

A. Either be able to directly enter a ZFW in to the aircraft, enter the fuel, and the aircraft balances itself, like many other payware addons available on the market.

B. Correct the fuel planner so that a TOTAL fuel amount correctly updates the CG.

 

1. Using a previous OFP I generated in PFPX and from a VA I fly with, 243 pax, ZFW 155,700kg. Flight is from YMML to VHHH, required fuel is 59,700kg.

 

Sliders moved to match ZFW (note the information in the balance section, bottom left.

TOW %MAC 28.0%

ZFW %MAC 31.1%

Trim UP 3.5

 

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2. Entered total fuel amount of 59,700kg. Note, that none of the fuel or balance information on the left hand side updates.

 

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3. Generate loadsheet, no image, self explanatory.

 

4. Init the loadsheet. Like you said, the data here is transferred (ZFW, ZFWCG and Trim values), but the trim figure hasn't taken in to account the self entered TOTAL fuel value.

 

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5. Images showing the data transferred. However, the trim value is only based of the 35,730kg of fuel in the running total section of the fuel planner, not what I have manually entered in to the TOTAL figure.

 

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Now if I enter a bunch of parameters in to the fuel planner to bring the running total up to 59,700kg, I actually get the correct trim values from the fuel planner, based on the correct amount of fuel loaded to the aircraft of UP 2.3.

 

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This leaves the trim a total of 1.2 units out. Also, the TOWCG is vastly different to the aircraft calculated one as well.

 

I, personally, do not like this system. The system is simple to use, yes, but invalid for aircraft loading at the moment. Not to mention, the fuel planning data it produces is grossly inaccurate (but that's another topic altogether).

 

The captain does not individually move passengers and cargo around to get a desired CG. This is done by other people. I've got other addons (e.g. FSLabs, PMDG) where I can enter a ZFW in to the aircraft, and it provides a balanced aircraft based on that figure. I have the option to fiddle with different ZFWCG's if I wish, but generally this figure is going to be optimised prior to being given to the flight crew.

 

Is the entering of a ZFW directly in to the MCDU to generate a load (e.g. on LSK4L of the LOAD and FUEL page) something that can be implemented in the future?

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  • 7 months later...

Excellent point Sharkbait. I enjoyed reading the back and forth responses regarding this topic.

 

I personally don't like this feature of using the fuel planner and having to input the data (whether manually or via fuelplanner) into the MDCU3. They should just get rid of it altogether. I think the ideal feature should be like the real A320, that you go to the INIT B page and insert all the data one gets from the OFP and loadsheet from loadcontrol (the folks who do the weight and balance at the airport for the flight) and that's it. No need to go to the load and fuel page in MDCU3.

 

For all fun and game, attached is the trim sheet I use for my flights using the A320IAE.

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  • Deputy Sheriffs

First, this topic is quite old and outdated.

 

There was a update to the Fuelplaner some time ago. It now also takes the fuel into account for the CG. That wasn’t before at all.

 

I will now close this topic.

 

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