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Really struggling with load charts & take off charts

Guest Brett Campany

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Guest Brett Campany

I just can't get my head around them. I'm using the Aviation Theory Centre books and the guys at work will give me a hand in the coming weeks but they just don't make sense to me yet.


Can anyone shed any light on them for me at all? I want to knock over my BAK in the next two weeks or so. This is really the only thing I'm having problems with.




Cheers all.



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Mate, maybe at the moment you may be trying to understand the theory too much - which is giving you grief.


Not sure what system you are using, but at the moment maybe just work through the sheet and not get too concerned with the theory. Once you start playing around it will start to "work"


Just be careful you don't make little mistakes when taking your totals and then plot them. For example:


In System B - you plot the Weight and the Moments, but


In System C you plot the Weight and the CG Arm


I know I used to get caught out on this all the time


Just do the calculations as per the form. IE if the pilot weighs XXkgs , multiply by the XXX. Same for the fuels and passengers. Once you get your totals add them together and plot them. Then have a play and change the weights to see how the dot on the sheet moves about.


I have the atc book so if you want to talk one through just PM me and Ill give you my number.


I always like the example of two kids sitting on a seasaw, if one moves further up or down the seasaw, or puts on an extra 20kg the seasaw wont be balanced. But if you move one of them or remove some weight they will return to balance.



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My other dumb examples that may help are


Next time your at work - have a look and see if you can see a freight plane (such as a Metro) being loaded.


Although it can carry 1900kgs of freight it needs to be spread out. If you took a 1500kg box and sat it in one of the rear bays the plane will tip backwards (hopefully end up on the tailstand), so if you were the pilot how hard do you think it would be to fly in that condition. But if you could break up that box and spread its load accross all the bays the plane will sit even and will be flyable.


The other real dumb and so not technically correct example is: :)


Using the seesaw idea above, imagine instead of a kid on one end it is your engine. if you pretend its a plane and you and your mates all jump on and sit in the right places the seasaw will stay balanced. But if your mate (as kids do) decides he wants to jump out of his seat and stand on the bonnet (hmm I mean cowling) the engine side of the swing will go down and hit the ground - Now in this case you havnt exeed the maximum weight of the seesaw all thats happened is the weight has moved. So to correct it you have to add more weight to your side or move some weight on your side (probably back further) or push him off.


The only difference is if you were doing this at a playground you would "move a bit here and there" by guesswork. But i the case of aircraft load sheets someon has done all the ork for you.


As an extreme dumb example:


You have your car and you put all the heavy things you are taking away with you on the roofracks. Your car can carry the weight and if you drive down the road at 80kph in a straight line - its all good. (so a bit like the Normal in a loadsheet)....... but if you decide you are going to drive faster and go on twisty roads, do some hairpins and handbrakies - guess what - you will probably roll over.


Because your CG is too high. So in that configuration your load sheet probably looked fine for Normal Ops but would not have been within the Utilty Box.


So now you still want to carry all the stuff and do handbrakies...If you move the load into the boot and rear seat, maybe add or take out some petrol and then replot it on your loadsheet - bang it will now fall inside the Utilty box.


Why - beacause you have the same load onboard but you loaded it such a way that the CG hasnt been shifted so that you roll your car


Dumb examples I know - but they work for me :)



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source of Data.


Have you gone to the RAAus website and gone to groundschool and weight and balance?


I think at the moment there are about (3) systems for calculating weight and balance.


I believe that you need to thoroughly understand the principles involved, which are common to all systems. This helps to prevent major errors.


I don't think that you are the only one having difficulty as the subject seems to have been made complex. over time.


To commence using any system you need the particular aircraft's BASIC weight, and balance point. (that's basic and pretty straightforward.)


any weight added will obviously add to the weight, but where you stow it will change the balance point. (Unless the CofG of the weight added co-incided with the existing balance point.)


You will come across the term "moment". Which gets back to your "see-saw". The factors involved in causing moment to exist are a "force" ( weight or mass ) and a distance and this causes a "turning effect" expressed in the same type of way as a torque figure.. The distance however is expressed as being from a datum point, such as the drive flange of the engine , or the wing leading edge, or even some point forward of both. Enough for now. Read the stuff on the RAAus site. Nev..



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Guest Brett Campany

Cheers guys, I'm onto the RAAus site and will look through that, just need to persevere with it. My instructor has me doing the PPL BAK so that's why it's so relevant.


I'm not sure what the difference is between the PPL & RAA BAK but they've suggested I do it this way.


Cheers again



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Have a look at Bob Taits theory books as well, as i found them a bit simpler to understand to begin with, then i moved onto the other aviation theory books for the other types of load sheets (bravo/charlie etc.)Cheers

+1 for Bob Taits books, alot easier to understand. :thumb_up:



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Takeoff charts shouldn't give you too much grief if you think logically about your answer. As in, if the conditions are 10 knots of headwind, 3 pob and full fuel in a Cessna 172 on gravel, think to yourself, how long would it take to get off in a 172 based on the ones I've seen at my local field........ and your answer is 400 metres, you should be able to compare and check your answer for reasonableness. Atleast that way you'll realise if you've made a big mistake somehow.


Admittedly a grass runway with a few degrees of slope at MTOW on a 35 degree day might be hard to estimate!



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Guest pelorus32

All you need to know


This is all you need to know about loading systems:


A robed gentleman here got it wrong. This could happen to you if you get it wrong as well.




Then you'd feel like a bit of a donkey 006_laugh.gif.0f7b82c13a0ec29502c5fb56c616f069.gif











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