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Practical CPL Weight and Balance

  • Naythan91
  • Topic Author

Naythan91 created the topic: Practical CPL Weight and Balance

Hey there, I am coming up to my CPL licence test in the next few weeks but i am still having trouble with the weight and balance scenarios and getting through them as efficiently and accurately as possible. I had no issues with the casa exam as the process to go through was clear in my mind as the text book was great and the flow charts worked wonders! but with the practical side of things i seem to be having a bit of trouble i wonder if you guys could please help me out as it causes alot of undue stress when preparing for my flights.

My main issue is time and a logical approach to the question. The ato i am going to be flying with likes us to do a weight and balance for each of the legs which is very time consuming but my understanding is that you only really need to do it for the limiting leg. Here's my last weight and balance scenario.

The aircraft i fly is a C182
Max ramp weight 1410kg
MTOW 1406kg
MLW
Fuel burn 50 lph
fixed res 45 min = 38 L
var res 15% ff

I have found that with 99% of the problems that if you are under the weights you are in balance.

You are going on a charter flight from:

Point cook- essendon - mount gambier- Raglan ala

Pt cook > EN: 10 minutes
En > MTG: 100 minutes
MTG > Raglan: 30 minutes

You have 50 litres of fuel already in the aircraft. fuel is available at Mount Gambier: fuel is NOT available at Essendon. You have 2 passengers at point cook ( 95kg and 95kg). You will be picking up one more passenger at Essendon (75kg) before your flight to Mount Gambier.
Pilot weighs 80kg

1) how much fuel is required to be uploaded at point cook?
2) how much baggage can we take from point cook?

^^ That is a Typical scenario is there a quick way to attack these questions i.e., like the flow charts?
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  • Naythan91
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Naythan91 replied the topic: Practical CPL Weight and Balance

MLW 1338
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  • Richard

Richard replied the topic: Practical CPL Weight and Balance

Hi Naythan,

We don't have enough information on this particular scenario to attack it as an example but since you are asking for general advice on how to approach it practically, here are a couple of pointers:

First off, in the Cessna 182, as you quite rightly surmised, it is hard to get the aircraft out of balance with standard loads. Your biggest problem is going to be overloading or exceeding limiting weights. This doesn't excuse you from double checking the balance for each sector though!

Secondly, with this kind of planning, the easiest way to approach it is to simply work backwards from the final destination and back through all the intermediate points until you finally get back to the take-off point. For each of the sectors you use beetle diagrams with the conditions of that sector and by the time you get back to the origin you have your take-off conditions.

In your example, you would first consider the Mt Gambier -> Raglan sector.

What is the maximum landing weight at Raglan? You will be turning up with 3 passengers+gear+ pilot. If you want to maximise the gear you may want to arrive with minimum fuel (i.e. with reserves intact) but that is only assuming fuel is available at Raglan. If no fuel is available then you will need to ensure you include fuel to the next refuelling point in your landing weight at Raglan. Perhaps the weather is dodgy so in that case you might want to carry extra fuel. Whatever the situation of the scenario, simply workout what you want on board the aeroplane at the destination.

Use the beetle diagram as usual to find the maximum take off weight at Mount Gambier which allows you to end up at Raglan in the condition you require.

Now, once you have worked out the constellation for departure from Mt Gambier, you now know what you need to have on board at departure from Mt Gambier. There's a few more things to consider though.

Can you refuel at Mt Gambier? If so, you can simply arrive at Mt Gambier with minimum fuel and then refuel with enough to get you to Raglan. If not then you know your arrival weight at Mt Gambier must include the fuel to get you on to Raglan as well.

Let's assume you will refuel at Mt Gambier and want to maximise cargo, You want to arrive at Mt Gambier with minimum fuel and you will have 3 passengers + gear + pilot on board. Do the Beetle diagram and find the MTOW for departure from Essendon with pilot, 3 pax, max gear and the minimum fuel for the Mt Gambier sector.

Now you have worked backwards to Essendon. You know you are departing Essendon with 3 pax but you are only arriving with 2. So the beetle diagram for arrival at Essendon will be for an arrival with 2 passengers and the fuel you worked out you needed to get you on to Mt Gambier with maximum cargo.

This is an interesting kind of planning situation which we all encounter in real life on multi-sector flights. I'll leave the calculations to you since you have all the data but if you'd be willing to post any workings here, I'm sure it would be of interest to other students as a real world example.

So, to summarise, when approaching this kind of problem it is easiest to work logically backwards from the "known" condition (e.g. your condition on arrival at Raglan) back towards the "unknown" condition (e.g. at your departure from Point Cook).

Don't forget to cast an eye over the balance for each sector as well. That is still going to be a legal requirement even if you will be inside the envelope 99% of the time.

Cheers,

Rich
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