Airbus Mass & Balance Question
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Airbus Mass & Balance Question
Hi Everyone,
I recently came across a question which asked
" how would you adjust mass and balance load sheet if the APU was removed for maint "
A have searched everywhere but to no avail..
Any suggestions?
I recently came across a question which asked
" how would you adjust mass and balance load sheet if the APU was removed for maint "
A have searched everywhere but to no avail..
Any suggestions?
Moderator
Putting aside the question at #3, the solution is the same as any other mass added/removed problem .. add/subtract the weight and moment changes into the calculation mix and redo the CG division ...
Specifically, for the loadsheet, the process will be defined .. generally either a simple adjustment to the entry data or a correction in the sheet.
Specifically, for the loadsheet, the process will be defined .. generally either a simple adjustment to the entry data or a correction in the sheet.
Was the question related to engineering or piloting?
Surely the APU is part of the Basic Empty Mass (BEM), and the BEM is part of the Fry Operating Mass (DOM) . Assuming that the aircraft is permitted to fly without an APU, the engineering department should recalculate the BEM, DOM and the DOM Index as part of the paperwork for the APU removal.
These recalculated figures will then be the starting point for the loading staff filling in the load sheet.
Surely the APU is part of the Basic Empty Mass (BEM), and the BEM is part of the Fry Operating Mass (DOM) . Assuming that the aircraft is permitted to fly without an APU, the engineering department should recalculate the BEM, DOM and the DOM Index as part of the paperwork for the APU removal.
These recalculated figures will then be the starting point for the loading staff filling in the load sheet.
Last edited by keith williams; 26th Mar 2014 at 08:11. Reason: Forgot that airbus load sheets start at the DOM and DOI.
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Hi,
Towteambase - I've had APU inop many times, however never APU removed not sure if you can
John & Keith - I am thinking about it from a line Capt's point of view, say you had the apu removed for whatever reason, and the ground staff hand you a loadsheet with the regular BW and BI used. With regards to weight , you are now lighter than loadsheet, ( some would say more conservative when calculating performance ) however with regards to trim, the CG would shift quite a bit, which would have adverse effect on rotation if the THS was not correctly set ( results from correct TO GW C of G )
So how would I correct this weight and trim on loadsheet, or verify everything if a corrected loadsheet was handed to me ?
Thanks
Towteambase - I've had APU inop many times, however never APU removed not sure if you can
John & Keith - I am thinking about it from a line Capt's point of view, say you had the apu removed for whatever reason, and the ground staff hand you a loadsheet with the regular BW and BI used. With regards to weight , you are now lighter than loadsheet, ( some would say more conservative when calculating performance ) however with regards to trim, the CG would shift quite a bit, which would have adverse effect on rotation if the THS was not correctly set ( results from correct TO GW C of G )
So how would I correct this weight and trim on loadsheet, or verify everything if a corrected loadsheet was handed to me ?
Thanks
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Sorry, but are you 'for real'?
You started with
- where was this 'question'?
- hand it back to them and tell them to get it right.
- do you know what/do you have/ a load and balance manual is in the aircraft documents set?
Have you had ANY load and balance training? If not, or even 'if' you need to read Keith W's post. Which airline have you been 'operating' for when you have "had APU inop many times"?
Removal of APUs is not uncommon, as would also be airstairs. Would you know what to do about that? What about a change in catering? How do you cope with that? Do you know what an aircraft 're-weigh' is?
You started with
Originally Posted by Lamboo
I recently came across a question which asked
and the ground staff hand you a loadsheet with the regular BW and BI used.
or verify everything if a corrected loadsheet was handed to me ?
Have you had ANY load and balance training? If not, or even 'if' you need to read Keith W's post. Which airline have you been 'operating' for when you have "had APU inop many times"?
Removal of APUs is not uncommon, as would also be airstairs. Would you know what to do about that? What about a change in catering? How do you cope with that? Do you know what an aircraft 're-weigh' is?
You are obviously correct in saying that the absence of the APU would have a marked effect on handling.
There are lots of situations in which engineering actions change the basic weight and balance of an aircraft. These include the embodiment of some types of modifications and also some types of structural repairs. The removal of an APU would fall into the same category.
Whenever these type of action are carried out the required paperwork includes the recalculation of the BEM, DOM and DOI. So if the engineers are doing their job properly, the loaders and pilots just use an updated load and trim sheet and complete it in the usual manner.
As I have said above, if the engineers are doing their work properly the loaders and pilot do not update the DOM and DOI in the loadsheet. They simply use the updated figures that have been provided by the engineers.
Again, you should not need to check it. Do you check the calculation of the BEM, DOM and DOI for every flight after any significant engineering work has been done?
I suppose that there might be a situation in which you had reason to suspect that the figures had not been updated. If, for example you flew the same aircraft every day and had become so familiar with the DOM and DOI that you could remember them. Then if the APU was removed one day and you spotted the fact that the figures in the load sheet had not changed, you would obviously need to have some checks done. But to do this you would need to go back to the engineering records, so it's not the kind of thing that you could do on the ramp.
There are lots of situations in which engineering actions change the basic weight and balance of an aircraft. These include the embodiment of some types of modifications and also some types of structural repairs. The removal of an APU would fall into the same category.
Whenever these type of action are carried out the required paperwork includes the recalculation of the BEM, DOM and DOI. So if the engineers are doing their job properly, the loaders and pilots just use an updated load and trim sheet and complete it in the usual manner.
So how would I correct this weight and trim on loadsheet, ?
or verify everything if a corrected loadsheet was handed to me
I suppose that there might be a situation in which you had reason to suspect that the figures had not been updated. If, for example you flew the same aircraft every day and had become so familiar with the DOM and DOI that you could remember them. Then if the APU was removed one day and you spotted the fact that the figures in the load sheet had not changed, you would obviously need to have some checks done. But to do this you would need to go back to the engineering records, so it's not the kind of thing that you could do on the ramp.
Moderator
the ground staff hand you a loadsheet with the regular BW and BI used
Unless this is something envisaged within your operations (and details would be cited in the relevant Ops Manual data) it indicates a major screw up. Requesting that it be fixed would be the appropriate course of action. The SMS would expect that you also raise it for investigation via whatever system protocols you have in place.
If the relevant figures are specified in your documentation, then it is a simple matter to fix for the load sheet calculation. However, I would be surprised if this were the case.
Keith's comment re recalculation is very appropriate. The RWA cheat sheet would, almost certainly, show the delta CG to be outside the tolerance and require a revised Load Data Sheet (by whatever name).
the CG would shift quite a bit
I'm not an Airbus man so I am presuming the APU is in the tail in the normal manner ? If so .. the CG would move forward BIG time and require some definite management.
.. and, make no mistake about it .. significantly screwed up CG calculations (or "correct" calculations with incorrect loading) have killed many a good pilot in the past and, unfortunately, will do so again in the future when the situation arises and it of sufficient error.
Unless this is something envisaged within your operations (and details would be cited in the relevant Ops Manual data) it indicates a major screw up. Requesting that it be fixed would be the appropriate course of action. The SMS would expect that you also raise it for investigation via whatever system protocols you have in place.
If the relevant figures are specified in your documentation, then it is a simple matter to fix for the load sheet calculation. However, I would be surprised if this were the case.
Keith's comment re recalculation is very appropriate. The RWA cheat sheet would, almost certainly, show the delta CG to be outside the tolerance and require a revised Load Data Sheet (by whatever name).
the CG would shift quite a bit
I'm not an Airbus man so I am presuming the APU is in the tail in the normal manner ? If so .. the CG would move forward BIG time and require some definite management.
.. and, make no mistake about it .. significantly screwed up CG calculations (or "correct" calculations with incorrect loading) have killed many a good pilot in the past and, unfortunately, will do so again in the future when the situation arises and it of sufficient error.
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BOAC - yes I am for real, no botnet here ...
So answer you : -
1) This question can be found in my Airline's command preparation booklet. If you want a copy or want to know which airline I work for pm me.
2) I have been handed a loadsheet where the BW used was for a training flight not with 14 crew and full catering ( that's a difference of 6700kg ) so I don't trust these people, and in the end I will have to sign it not him, you or yogi bear.
3) yes I am quite familiar with my companies' L & B manual. I also check my calculated values vs the loadsheet to check that everything is normal not to end up in a nasty situation ( see above)
4) yes I have done load training, on many aircraft and am also certified to( fly freighter) do freighter load and balance.
5) I will tell you which airline I was working for when I had apu inop quite often if you pm me.
6) I certainly know what to do with a change In catering, potable water, or additional crew. I know what a re weigh is, I asked the question as the airline I currently operate for utilizes their AC to the max, and I doubt they will have time to re weigh a/c between flights.
Keith - thanks for that, before I posted I would have thought that that was the reasonable thing to do, however I thought I would just ask maybe I'm missing something.
Cheers
John - thanks indeed I will check what the local regulations say about this and maybe draw attention to it to my tech pilot. Unfortunately rouge cg changes on ground or in flight have killed a lot, even recently :-(
So answer you : -
1) This question can be found in my Airline's command preparation booklet. If you want a copy or want to know which airline I work for pm me.
2) I have been handed a loadsheet where the BW used was for a training flight not with 14 crew and full catering ( that's a difference of 6700kg ) so I don't trust these people, and in the end I will have to sign it not him, you or yogi bear.
3) yes I am quite familiar with my companies' L & B manual. I also check my calculated values vs the loadsheet to check that everything is normal not to end up in a nasty situation ( see above)
4) yes I have done load training, on many aircraft and am also certified to( fly freighter) do freighter load and balance.
5) I will tell you which airline I was working for when I had apu inop quite often if you pm me.
6) I certainly know what to do with a change In catering, potable water, or additional crew. I know what a re weigh is, I asked the question as the airline I currently operate for utilizes their AC to the max, and I doubt they will have time to re weigh a/c between flights.
Keith - thanks for that, before I posted I would have thought that that was the reasonable thing to do, however I thought I would just ask maybe I'm missing something.
Cheers
John - thanks indeed I will check what the local regulations say about this and maybe draw attention to it to my tech pilot. Unfortunately rouge cg changes on ground or in flight have killed a lot, even recently :-(
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OK
- no thanks - see 3)
Only 6700kg difference means no pax on either flight - ie positioning or training - and many airlines do not require a loadsheet completed for these in any case. This will be in your ops manual. Presumably you will not be able to exceed any load limitations on those flights anyway.
- perhaps they are testing your knowledge of company manuals - it may be that APU removal is an item in the load and balance manual with 'standard' figures, but see 6).
- nor will they have time to remove the APU 'between flights'! I'm not actually sure an actual 're-weigh' is required for such an event if standard figures are available but the W&B details MUST be amended by engineering. Often done by a 'Notice to Aircrew' or whatever you would call it. Same for airstairs/oven/seats removal. In which case, in 3), you sit clutching the 'Notice' in one hand and you check buggins' load sheet against that. If it is wrong, smack him/her with a wet fish and send them back to the office. You should never have to adjust for APU removal yourself, not even as a Captain in your airline. I know of one airline where the No2 engine (727) was 'removed' 'between flights' by a catering truck, but I don't think the Captain accepted the aircraft after the walk-round.
1) This question can be found in my Airline's command preparation booklet. If you want a copy or want to know which airline I work for pm me.
2) I have been handed a loadsheet where the BW used was for a training flight not with 14 crew and full catering ( that's a difference of 6700kg ) so I don't trust these people, and in the end I will have to sign it not him, you or yogi bear.
3) yes I am quite familiar with my companies' L & B manual. I also check my calculated values vs the loadsheet to check that everything is normal not to end up in a nasty situation ( see above)
6) I certainly know what to do with a change In catering, potable water, or additional crew. I know what a re weigh is, I asked the question as the airline I currently operate for utilizes their AC to the max, and I doubt they will have time to re weigh a/c between flights.
Moderator
so I don't trust these people
At day's end, everyone is prone to making mistakes ... seen similar sorts of W&B screw ups over the years myself. The crew is the last line of defence so you need to be on the ball with this stuff and a bunch of other stuff as well.
Guess that's why the Commander doesn't drop the ball and keeps a useful level of suspicion from sign on to sign off ...
If you aren't comfortable - doesn't matter whether you turn out to be right or wrong - query it and get the other guy to walk you through until you are OK with what is being presented .. and don't sign off on it until you are satisfied that it is OK to do so.
Your company's system should incorporate one guy/group doing it .. and the crew checking things in a reasonably independent manner. Mistakes are made but they don't bite if they are detected and corrected.
doubt they will have time to re weigh a/c between flights
Not a consideration and not necessary. The required exercise is a standard paper warfare thing on the RWA/LDS.
Same for airstairs/oven/seats removal
Exactly .. and done the same way .. just the numbers change.
but I don't think the Captain accepted the aircraft after the walk-round
.. love it.
At day's end, everyone is prone to making mistakes ... seen similar sorts of W&B screw ups over the years myself. The crew is the last line of defence so you need to be on the ball with this stuff and a bunch of other stuff as well.
Guess that's why the Commander doesn't drop the ball and keeps a useful level of suspicion from sign on to sign off ...
If you aren't comfortable - doesn't matter whether you turn out to be right or wrong - query it and get the other guy to walk you through until you are OK with what is being presented .. and don't sign off on it until you are satisfied that it is OK to do so.
Your company's system should incorporate one guy/group doing it .. and the crew checking things in a reasonably independent manner. Mistakes are made but they don't bite if they are detected and corrected.
doubt they will have time to re weigh a/c between flights
Not a consideration and not necessary. The required exercise is a standard paper warfare thing on the RWA/LDS.
Same for airstairs/oven/seats removal
Exactly .. and done the same way .. just the numbers change.
but I don't think the Captain accepted the aircraft after the walk-round
.. love it.
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The aircraft would have to be granted a W/B change allowed by standard practices executed by the companies engineering department (approved by the CAA & MFGR) for this change. Really simple, but with all the red tape I doubt it would happen in today's world unless under extreme circumstances and for a only one time non profit ferry permit!
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A major Airline i work with publishes corrections for DOW/DOI in case of APU removal (A320 family).
Corrections:
A319 : -140kg // -2.2 iu
A320 : -130kg // -2.2 iu
A321 :-140kg // -2.7 iu
these are quite significant CG changes as you would expect.
Corrections:
A319 : -140kg // -2.2 iu
A320 : -130kg // -2.2 iu
A321 :-140kg // -2.7 iu
these are quite significant CG changes as you would expect.
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Again, for your upgrade, the correct answer is you do not have to. It is an engineering function and if you have no modified W&B figures issued then don't accept the aircraft.
Of course, if we are talking 'life and death and drama' stuff then you would have to modify it yourself, but a bit fanciful, don't you think? Mind you, if I were in that much of a hurry I'd whack on a bit more trim and go without a loadsheet!
Of course, if we are talking 'life and death and drama' stuff then you would have to modify it yourself, but a bit fanciful, don't you think? Mind you, if I were in that much of a hurry I'd whack on a bit more trim and go without a loadsheet!
