MD-80 loadsheet - Adjusted Weight Loading System.
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I've had a play with the relationships cited in post #13 trying to end up with the two earlier relationships from first principles and starting with the presumed guidance of #3 .. with little success. Possibly my lack of imaginative manipulation so I need a little guidance regarding the goalposts, I guess.
I am presuming that each intends to achieve the same result, viz., a concatenation of a weight and an index .. in each case with the arm information represented as %MAC and stab trim setting units, respectively.
Now I see that scotiat claims some considerable competence in the subject in his cited website so, perhaps, I can ask him to give the horse a touch of the spur by setting out a simple example calculation for, say, a postulated light aircraft. That should sort out the confusion with terms and definitions very promptly.
As I suggested earlier, this is an important topic from a safety viewpoint and it is worth working through the detail for the benefit of
(a) me .. as we don't appear to use the technique in Australia and, at this point, I am a tad confused in that I appear to be unable to derive what ought to be a comparatively trivial engineering calculation
(b) the new chums .. as they possibly know less than I do about the weight control subject.
I am presuming that each intends to achieve the same result, viz., a concatenation of a weight and an index .. in each case with the arm information represented as %MAC and stab trim setting units, respectively.
Now I see that scotiat claims some considerable competence in the subject in his cited website so, perhaps, I can ask him to give the horse a touch of the spur by setting out a simple example calculation for, say, a postulated light aircraft. That should sort out the confusion with terms and definitions very promptly.
As I suggested earlier, this is an important topic from a safety viewpoint and it is worth working through the detail for the benefit of
(a) me .. as we don't appear to use the technique in Australia and, at this point, I am a tad confused in that I appear to be unable to derive what ought to be a comparatively trivial engineering calculation
(b) the new chums .. as they possibly know less than I do about the weight control subject.
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Guidance
Hello John,
I'm going to send you the entire chapter from which I posted the image on post #13. It may be of some help. As you rightly said earlier, there is little or no information on this method calculation, and maybe for a good reason. Modern systems certainly don't use it that often.
The Index equation for adjusted weight makes sense. But the %MAC one needs clarification.
Maybe somebody out there would have a weight and balance manual from a time when this was popular that would explain further. I have a USAir BAe-146 Pilot's handbook that uses this method but no explanation, only a sample. Also I flew a YS-11A from Mid-Pac airlines that used the same. Seemed to be popular in the US circa the 80's and early 90's.
We will crack it I'm sure.
I'm going to send you the entire chapter from which I posted the image on post #13. It may be of some help. As you rightly said earlier, there is little or no information on this method calculation, and maybe for a good reason. Modern systems certainly don't use it that often.
The Index equation for adjusted weight makes sense. But the %MAC one needs clarification.
Maybe somebody out there would have a weight and balance manual from a time when this was popular that would explain further. I have a USAir BAe-146 Pilot's handbook that uses this method but no explanation, only a sample. Also I flew a YS-11A from Mid-Pac airlines that used the same. Seemed to be popular in the US circa the 80's and early 90's.
We will crack it I'm sure.
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Excel file of loadsheet
Hi! Can you send me the Excel File of the Loadsheet that you designed for the MD-80? I just want to have a good reference because im also designing a loadsheet of both dornier & boeing aircrafts. by the way this is my email. [email protected].
Last edited by Jetdriver; 11th Jan 2013 at 03:02.
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Adjusted weight loading
John,
I have specialised in aircraft weight and balance for over 18 years.
I fully understand the differences between dropline, tabular and AWIS systems.
I apologies if I have added to any confusion, but I will happily send sample loading systems and substantiation reports for AWIS systems if you provide a contact email address.
I cannot post this on the web as it is company IP.
I fully appreciate that w&b is a very safety critical issue and I have also seen many examples of how trimsheets can be produced with serious errors when the author has little knowledge or experience. Thus why I am willing to assist.
I have specialised in aircraft weight and balance for over 18 years.
I fully understand the differences between dropline, tabular and AWIS systems.
I apologies if I have added to any confusion, but I will happily send sample loading systems and substantiation reports for AWIS systems if you provide a contact email address.
I cannot post this on the web as it is company IP.
I fully appreciate that w&b is a very safety critical issue and I have also seen many examples of how trimsheets can be produced with serious errors when the author has little knowledge or experience. Thus why I am willing to assist.
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Excel Load Sheet
Hi john
I really enjoyed reading all the previous comments that s helped me to understand a lot of things.
I am a flight dispatcher in a handling comapany so i work with many airlines and i have to do many manual load sheets so i got the idea to do an excel load sheet wich i found realesed already here on this formum
finally i realesed my own excel load sheet of the vueling airline a fleet of 41 aircratf A320/214.
I want to share it with you, i compare it many times with the automatized load sheet and the result were 95% the same.
here you will find a jpeg copy maybe you help me for any detaills
I really enjoyed reading all the previous comments that s helped me to understand a lot of things.
I am a flight dispatcher in a handling comapany so i work with many airlines and i have to do many manual load sheets so i got the idea to do an excel load sheet wich i found realesed already here on this formum
finally i realesed my own excel load sheet of the vueling airline a fleet of 41 aircratf A320/214.
I want to share it with you, i compare it many times with the automatized load sheet and the result were 95% the same.
here you will find a jpeg copy maybe you help me for any detaills
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Discrepancy ought to be rather less than that.
Generally, the main bits which give problems are associated with
(a) centroid approximation for a loading area
(b) figuring variable things such as occupant movement in flight
(c) linearising fuel arms
and then the error analysis (which ought to be, but is not always, done) which may fudge the sheet CG limits to make the completion conservative.
For spreadsheets, if they are to be used by others, the main concern is protecting against third party errors in use compromising the calculated results.
By all means send me a copy and I'll have a looksee.
Generally, the main bits which give problems are associated with
(a) centroid approximation for a loading area
(b) figuring variable things such as occupant movement in flight
(c) linearising fuel arms
and then the error analysis (which ought to be, but is not always, done) which may fudge the sheet CG limits to make the completion conservative.
For spreadsheets, if they are to be used by others, the main concern is protecting against third party errors in use compromising the calculated results.
By all means send me a copy and I'll have a looksee.
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Excel Load Sheet
hello john
I do i understand all those problems in the CG, moment and fuel effect wich are very difficults to calculate and generate a perfect load sheet.
But we have the right to try and learn from our mistakes.
Anyway i will send you the excel load sheet wich i realsed with a pdf file explaining how to use it, I will send it to this email [email protected]
I will await your reply.
I do i understand all those problems in the CG, moment and fuel effect wich are very difficults to calculate and generate a perfect load sheet.
But we have the right to try and learn from our mistakes.
Anyway i will send you the excel load sheet wich i realsed with a pdf file explaining how to use it, I will send it to this email [email protected]
I will await your reply.
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Did you get anywhere??
Hello all
I'm just wondering if you ever got anywhere with this as its highly topical for me just now?... We are putting some aircraft into someone elses fleet and I am tasked with creating a loadsheet similar to their own in order to reduce differences between types, a trawl of the web returned this discussion.
Unfortunately the people that are now responsible for their weight and balance don't seem to even understand that their loadsheet is an adjusted weight/stab loadsheet so when I ask for their loadsheet formula data they just provide the standard data from the WBM which I already have.
All I get from them is moving "x" passengers moves the trim by "x" units and can we do the same!
I am guessing they got the loadsheet from Mr.Boeing as a package and they are keeping their secrets close to their chests.
So I am left with the task of trying to deconstruct what they currently use in order to understand it and adapt it for a new type. Undoubtedly the variables can be cracked in time but the deadline is approaching and without the loadsheet type I cannot even start on operational margin calculations (the inaccuracies of this system will affect the envelope).
The last time I worked with adjusted weight loadsheets was in the 80s and to be honest thought them to be extinct.
If you got anywhere with understanding the logic I would be grateful to hear anything before I make a decision on if I can offer this type of sheet or not.
thanks
Nobby
I'm just wondering if you ever got anywhere with this as its highly topical for me just now?... We are putting some aircraft into someone elses fleet and I am tasked with creating a loadsheet similar to their own in order to reduce differences between types, a trawl of the web returned this discussion.
Unfortunately the people that are now responsible for their weight and balance don't seem to even understand that their loadsheet is an adjusted weight/stab loadsheet so when I ask for their loadsheet formula data they just provide the standard data from the WBM which I already have.
All I get from them is moving "x" passengers moves the trim by "x" units and can we do the same!
I am guessing they got the loadsheet from Mr.Boeing as a package and they are keeping their secrets close to their chests.
So I am left with the task of trying to deconstruct what they currently use in order to understand it and adapt it for a new type. Undoubtedly the variables can be cracked in time but the deadline is approaching and without the loadsheet type I cannot even start on operational margin calculations (the inaccuracies of this system will affect the envelope).
The last time I worked with adjusted weight loadsheets was in the 80s and to be honest thought them to be extinct.
If you got anywhere with understanding the logic I would be grateful to hear anything before I make a decision on if I can offer this type of sheet or not.
thanks
Nobby
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I have to apologise as I put the thread to one side and promptly forgot all about it. Bit busy for the next week or two but will endeavour to have a further play with it then.
Operators wanting to keep the same style of sheet can be a tad tedious but that's the way things go ....
Operators wanting to keep the same style of sheet can be a tad tedious but that's the way things go ....
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Dear John,
Your patient answers were perfect and enough.
It is not difficult, and you are not allowed to do mistakes in loadsheets! Nor to learn from mistakes on loadsheets! 
I hope the Captains will refuse to sign such papers.
Your patient answers were perfect and enough.
Originally Posted by Djallamitou
I do i understand all those problems in the CG, moment and fuel effect wich are very difficults to calculate and generate a perfect load sheet. But we have the right to try and learn from our mistakes.
I hope the Captains will refuse to sign such papers.
Moderator
The adjusted weight thing now makes a little more sense.
Recently, I came across an old (dating almost back to Pontius's days ..) tech paper presented by (I presume) the Boeing engineer who developed the system.
Apparently in the early second generation jet days, pre-electronic computer .. ie early 60s, some Boeing customer airlines were a bit anti-trim sheet style load systems and, while accepting that computers would do the day to day work in a few years to come, wanted a simple addition only style system in the meantime which combined all the bits (weight, CG, and stab trim calcs) in the one all singing all dancing technique. This then would allow them to do the load work on the turn around using traditional pencil and paper assisted by the old mechanical adding machine .. now, I remember those ... how many others here do ?
A chap named Saunders (the above engineer) came up with a concatenated system which, for the sake of some minor rubbery weight approximations, facilitated the requirement.
When I finish working through the technique (ie when I figure out just how it all works) and can relate it satisfactorily to the Boeing PPT link shown earlier, I'll come back with some explanation.
As nobbyknownowt suggested, the technique appears to have been intended as a (pre-computer) stopgap and probably has little relevance today other than as a curiosity .. albeit that some operators still hold to it as a procedural technique.
Recently, I came across an old (dating almost back to Pontius's days ..) tech paper presented by (I presume) the Boeing engineer who developed the system.
Apparently in the early second generation jet days, pre-electronic computer .. ie early 60s, some Boeing customer airlines were a bit anti-trim sheet style load systems and, while accepting that computers would do the day to day work in a few years to come, wanted a simple addition only style system in the meantime which combined all the bits (weight, CG, and stab trim calcs) in the one all singing all dancing technique. This then would allow them to do the load work on the turn around using traditional pencil and paper assisted by the old mechanical adding machine .. now, I remember those ... how many others here do ?
A chap named Saunders (the above engineer) came up with a concatenated system which, for the sake of some minor rubbery weight approximations, facilitated the requirement.
When I finish working through the technique (ie when I figure out just how it all works) and can relate it satisfactorily to the Boeing PPT link shown earlier, I'll come back with some explanation.
As nobbyknownowt suggested, the technique appears to have been intended as a (pre-computer) stopgap and probably has little relevance today other than as a curiosity .. albeit that some operators still hold to it as a procedural technique.
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CONSULTA
Estimados:
Buenas noches, mi nombre es Horacio, soy estudiante de Despachante de aeornaves, estoy realizando las practicas y me gustaría saber si a través de este foro, podría conseguir las planillas de carga del MD80, A320 A380, B747-800, ART72, CASA C-295, CD-10, CD9, E190, C-130, y sus respectivas tablas de index,
Disculpen se que es mucho pedir, pero me gustaría tener una ampliar variedad para la práctica, gracias y disculpen las molestias.
Este es mi correo [email protected] celular 541164878010.
Buenas noches, mi nombre es Horacio, soy estudiante de Despachante de aeornaves, estoy realizando las practicas y me gustaría saber si a través de este foro, podría conseguir las planillas de carga del MD80, A320 A380, B747-800, ART72, CASA C-295, CD-10, CD9, E190, C-130, y sus respectivas tablas de index,
Disculpen se que es mucho pedir, pero me gustaría tener una ampliar variedad para la práctica, gracias y disculpen las molestias.
Este es mi correo [email protected] celular 541164878010.
