Could anyone explain for me the second page of the LAA Weighing Form LAA/WB.
If you are doing the Empty Weight and CofG (Page 1), why on Page 2 do you have a section for variable load items. Surely this is for the Pilot to calculate before each flight if he chooses to. If it is for a W&B calculation, why are the weights for Pilot and Passengers dashed out on the form.
Also why is their a section for Weight and balance in service, or is the intention to use this form in-between 10yr weighings if you add or subtract equipment (avionics etc) without the need for re-weighing.
Maybe I have got it wrong and the form is not just for use at weighing time but for the pilot to continue to use for his pre-flight planning W&B, but would be happy to be enlightened.
John
http://www.wingweigh.co.uk
Aircraft Weighing and Form LAA/WB
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Flying John
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Aircraft Weighing and Form LAA/WB
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Chris Martyr
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Re: Aircraft Weighing and Form LAA/WB
Quite agree John. Page 2 appears to be full of "movable feast" type of items. Surely if one knows the empty wt. of ones aeroplane and its MAUW and the commensurate CofG stations then it's not too difficult to work out "all stations in between".
In the event of a modification affecting the aircraft C of G , then I would most certainly expect to see a new W/B form , or perhaps we've both misunderstood the content of page 2. Or maybe, as you mention , it's just an aid for use in flight planning.
Don't forget , you don't have to use this particular form anyway. I had my own one printed off , which directly reflects the W/B Form in Robert Lowe's book , 'Enjoy the Sky' , in which he builds an aircraft similar to my own.
CAP 562 also has an interesting section on weight/balance and shows a couple of different W/B Form formats .
In the event of a modification affecting the aircraft C of G , then I would most certainly expect to see a new W/B form , or perhaps we've both misunderstood the content of page 2. Or maybe, as you mention , it's just an aid for use in flight planning.
Don't forget , you don't have to use this particular form anyway. I had my own one printed off , which directly reflects the W/B Form in Robert Lowe's book , 'Enjoy the Sky' , in which he builds an aircraft similar to my own.
CAP 562 also has an interesting section on weight/balance and shows a couple of different W/B Form formats .
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Re: Aircraft Weighing and Form LAA/WB
John
the table at the top of page 2 is to record the maximum weights, arms, and moments of the variable loads so you can use them to calculate the most forward and rearward CG conditions in the table at the bottom of page 2.
This calculation defines the max and min weight of the pilot (121-189 lbs) and passenger(s) (0-189 lbs) to be used, which is why these weights are dotted out in the top table.
Don't be surprised if you can't get max fuel or baggage to stay within the CG range. Depending where the pilot, passenger, fuel, and baggage are situated will determine the max or min each should weigh when you calculate the max fore and aft CG.
Hope this helps.
John
the table at the top of page 2 is to record the maximum weights, arms, and moments of the variable loads so you can use them to calculate the most forward and rearward CG conditions in the table at the bottom of page 2.
This calculation defines the max and min weight of the pilot (121-189 lbs) and passenger(s) (0-189 lbs) to be used, which is why these weights are dotted out in the top table.
Don't be surprised if you can't get max fuel or baggage to stay within the CG range. Depending where the pilot, passenger, fuel, and baggage are situated will determine the max or min each should weigh when you calculate the max fore and aft CG.
Hope this helps.
John
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johnmichie
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Re: Aircraft Weighing and Form LAA/WB
ps
This form is only used for the initial weight and balance calculations, and to subsequent equipment changes. I'm about to add a two channel autopilot, this is too small a weight change to need a complete re-weigh but as there are many components at many different places I have submitted the calculations separately, not on this form.
How you do your daily calculations is up to you. I have my own form, which I can send you as an example if you PM me off list, but now of course I use SkyDemon.
John
This form is only used for the initial weight and balance calculations, and to subsequent equipment changes. I'm about to add a two channel autopilot, this is too small a weight change to need a complete re-weigh but as there are many components at many different places I have submitted the calculations separately, not on this form.
How you do your daily calculations is up to you. I have my own form, which I can send you as an example if you PM me off list, but now of course I use SkyDemon.
John
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Flying John
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Re: Aircraft Weighing and Form LAA/WB
Thankyou John and Chris, the main reason for asking is that I had invested in a professional set of Salter Brecknell Scales& ramps etc and wanted to offer a cost effective weighing service to other members. I wanted to be able to provide the results on the LAA's own forms LAA/WB(Metric) and LAA/WB(Imperial) and have this now as an app that you input the data too and it produces a PDF in either Metric or Imperial form to submit to LAA.
John
http://www.wingweigh.co.uk
John
http://www.wingweigh.co.uk
John Luck
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Ian Melville
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Re: Aircraft Weighing and Form LAA/WB
John, you still have a few steps to do before your website can be seen by the public.
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Re: Aircraft Weighing and Form LAA/WB
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Re: Aircraft Weighing and Form LAA/WB
Well I did the first weighings today and I must say Page 2 of the standard LAA form, especially the lower section "Loading Examples" strikes me as being nonsensical - but would be happy to be shown the error of my ways !.
For example, the text says for loading examples to show compliance a pilot weight of 121lbs to 189lbs and a min of one hour fuel, but then there is not a box to enter the weight and moment of one hours worth of fuel and the box says zero fuel totals, so you cannot do a worked example of most forward and most rearward loading.
It also says - after you have done the zero fuel CG (bear in mind the text says to do it with an hour of fuel) you go on to make the weight of the aircraft up to max gross weight with Fuel. In the example Jodel 117 I weighed this would involve adding 44gallons of fuel ! the tanks only hold 25galls.
So is it me. I cant believe a form that has been in-use since 2009 is wrong in this respect and I am not sure what it is trying to achieve.
My gut reaction is to discard the whole of page 2.
John
For example, the text says for loading examples to show compliance a pilot weight of 121lbs to 189lbs and a min of one hour fuel, but then there is not a box to enter the weight and moment of one hours worth of fuel and the box says zero fuel totals, so you cannot do a worked example of most forward and most rearward loading.
It also says - after you have done the zero fuel CG (bear in mind the text says to do it with an hour of fuel) you go on to make the weight of the aircraft up to max gross weight with Fuel. In the example Jodel 117 I weighed this would involve adding 44gallons of fuel ! the tanks only hold 25galls.
So is it me. I cant believe a form that has been in-use since 2009 is wrong in this respect and I am not sure what it is trying to achieve.
My gut reaction is to discard the whole of page 2.
John
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johnmichie
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Re: Aircraft Weighing and Form LAA/WB
John
There are four conditions where you must show the CG is within limits, namely
121 lb pilot and no passenger
121 lb pilot and 189 lb passenger
189 lb pilot and no passenger
189 lb pilot and 189 lb passenger
So four calculations are needed and you submit the two extremes, most forward and most rearward. It all depends where the fuel, pilot, and passenger(s) are situated. So far as I know, the one hour fuel requirement is for microlights to make sure they are legal with a sensible amount of fuel.
There is one anomaly, the rearmost CG could be with zero fuel or full fuel.
Don't ignore page two, it forms part of the aircraft documentation and a copy should be kept in the aircraft, especially when flying abroad.
I sometimes get confused with forms, most recently with flight testing autopilots. So I went to the LAA (you could phone), they are a friendly bunch and soon all was explained.
John
There are four conditions where you must show the CG is within limits, namely
121 lb pilot and no passenger
121 lb pilot and 189 lb passenger
189 lb pilot and no passenger
189 lb pilot and 189 lb passenger
So four calculations are needed and you submit the two extremes, most forward and most rearward. It all depends where the fuel, pilot, and passenger(s) are situated. So far as I know, the one hour fuel requirement is for microlights to make sure they are legal with a sensible amount of fuel.
There is one anomaly, the rearmost CG could be with zero fuel or full fuel.
Don't ignore page two, it forms part of the aircraft documentation and a copy should be kept in the aircraft, especially when flying abroad.
I sometimes get confused with forms, most recently with flight testing autopilots. So I went to the LAA (you could phone), they are a friendly bunch and soon all was explained.
John
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Chris Martyr
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Re: Aircraft Weighing and Form LAA/WB
Hi [Flying] John,
It's probably also worth remembering that the LAA W/B form is a "one size fits all" type of document and may cover rear-engined pushers, multi fuel tanks, single seat/four seat,,,etc,,etc,,
There are probably many instances whereby a w/b form tailored to a particular aircraft is infinitely more suitable than the LAA form.
My own aeroplane is a very basic single seater and as such only requires a very straightforward w/b form and the LAA item would be far too cluttered and unsuitable and most of the items on page 2 would just be crossed through with an N/A applied.
As said previously, CAA publication , CAP-562 Chapter 8 Leaflet 8-10 has a lot of very good basic gen regarding W/B including a couple of worked examples. One with a Jodel/Falconar and the other one [ which you probably won't need ] with a B.767 . It may be worth printing off some of the pages for your own use.
There is nothing that binds you to using the LAA W/B form and if the aircraft you are weighing has used a different and possibly more straightforward W/B form then it's probably worth sticking to that format.
It's probably also worth remembering that the LAA W/B form is a "one size fits all" type of document and may cover rear-engined pushers, multi fuel tanks, single seat/four seat,,,etc,,etc,,
There are probably many instances whereby a w/b form tailored to a particular aircraft is infinitely more suitable than the LAA form.
My own aeroplane is a very basic single seater and as such only requires a very straightforward w/b form and the LAA item would be far too cluttered and unsuitable and most of the items on page 2 would just be crossed through with an N/A applied.
As said previously, CAA publication , CAP-562 Chapter 8 Leaflet 8-10 has a lot of very good basic gen regarding W/B including a couple of worked examples. One with a Jodel/Falconar and the other one [ which you probably won't need ] with a B.767 . It may be worth printing off some of the pages for your own use.
There is nothing that binds you to using the LAA W/B form and if the aircraft you are weighing has used a different and possibly more straightforward W/B form then it's probably worth sticking to that format.
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Flying John
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Re: Aircraft Weighing and Form LAA/WB
Thankyou both for the replies.
I have CAP 562 and I find the actual Weight and CG part very easy and logical.
Since the LAA have produced a form for weighings I figured it would be best to use that for LAA aircraft. For my own GY80 I use a different format form, but it seems once on a permit one has to show the example loadings in accordance with BCAR Section S, but it is not the clearest of methods. For example it doesn't cater for fuel loads in two tanks at different lever arms or which tank should be used for each of the two examples.
Nevertheless it has been helpful to talk about it and see other peoples views and hopefully the LAA format sheets will be useable with some minor tweeks for different aircraft.
John
http://www.wingweigh.co.uk
I have CAP 562 and I find the actual Weight and CG part very easy and logical.
Since the LAA have produced a form for weighings I figured it would be best to use that for LAA aircraft. For my own GY80 I use a different format form, but it seems once on a permit one has to show the example loadings in accordance with BCAR Section S, but it is not the clearest of methods. For example it doesn't cater for fuel loads in two tanks at different lever arms or which tank should be used for each of the two examples.
Nevertheless it has been helpful to talk about it and see other peoples views and hopefully the LAA format sheets will be useable with some minor tweeks for different aircraft.
John
http://www.wingweigh.co.uk
Last edited by Flying John on Mon Apr 25, 2016 11:55 am, edited 2 times in total.
John Luck
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Re: Aircraft Weighing and Form LAA/WB
Another way to look at the LAA W&B form is that you are documenting the loading of different variables of different weights to show you aren't exceeding the aircraft's W&B limits at any time.
Your calculations will show how much fuel you can uplift (in various tanks if more than one), max weight of passenger(s) you can carry, max weight of baggage you can carry and then the practical combination of all of these variable factors for any given flight.
Tony Nowak
Your calculations will show how much fuel you can uplift (in various tanks if more than one), max weight of passenger(s) you can carry, max weight of baggage you can carry and then the practical combination of all of these variable factors for any given flight.
Tony Nowak
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Flying John
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Re: Aircraft Weighing and Form LAA/WB
Yes it is very useful for that purpose and I have converted it into a spreadsheet where you can change each of the variables and see how that affects the loading and CG for any particular flight.
It is more appropriate for doing a W&B calc before a flight, rather than for the 10 yearly weighing, although its useful to provide as a guide to the owner the typical load variations that will still keep him within the limitations set down by the designer or manufacturer.
John
It is more appropriate for doing a W&B calc before a flight, rather than for the 10 yearly weighing, although its useful to provide as a guide to the owner the typical load variations that will still keep him within the limitations set down by the designer or manufacturer.
John
John Luck
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