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Help working out Beetle diagram question

  • justus101@gmail.com
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justus101@gmail.com created the topic: Help working out Beetle diagram question

Hi all,

Working through some practice questions and just wanted to know what I did wrong on this one?

If I'm limited to landing of 2700kg, and burn up 33 gal flight fuel (90kg) wouldn't that make it 2790kg at take off? What am I missing?



Thanks all
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  • John.Heddles
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John.Heddles replied the topic: Help working out Beetle diagram question

I don't have a copy of Bob's text so I am not sure just what a "beetle diagram" is.

However, I suspect that this question has been reworked from an earlier version where the flight fuel was 76 kg and, somehow, the flight fuel plus variable from the original has become flight fuel in the later but the answer has not be edited appropriately.

The factors are not working out precisely but sufficiently so, with a bit of round off, for the above conclusion.

Bob will be able to resolve that discrepancy I am sure.

Engineering specialist in aircraft performance and weight control.
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bobtait replied the topic: Help working out Beetle diagram question

2790 kg would be the answer if the only thing you had to worry about was the landing weight. However, the Echo has a zero fuel weight limit of 2630 kg, and you are told you are to carry minimum fuel. So if the flight fuel is 33 gallons, the minimum fuel required at take-off is 33 x 1.15 plus the fixed reserve of 15 gallons. That is 144 kg. That means that another possible limit to take-off weight is the ZFW plus the weight of the fuel at take-off. 2776 kg is the closest answer.

The 'beetle diagram' allows you to always check to find if you are take-off weight limited, landing weight limited or zero fuel weight limited.
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  • John.Heddles
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John.Heddles replied the topic: Help working out Beetle diagram question

A quick question, if I may, Bob.

I omitted the MZFW case as I couldn't locate a FR value or information to determine such (although I should have caveated my post with that omission).

Does the FR value appear in the CASA booklet (V1 at 01Sep14 and I just couldn't find it ?) or is it published elsewhere and I have yet to locate it ?

Engineering specialist in aircraft performance and weight control.
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bobtait replied the topic: Help working out Beetle diagram question

Yes John. The students are given the workbook in the examination room. It can be downloaded from the CASA web site or from our own web site. Find a copy attached. You'll find the information on Page 18 para 3.

Cheers

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File Name: Day_VFR_Wo...k_v3.pdf
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  • John.Heddles
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John.Heddles replied the topic: Help working out Beetle diagram question

Thanks for that, good sir. One can only wonder at the need for a multiplicity of books from CASA with repeated data ...

Engineering specialist in aircraft performance and weight control.
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bobtait replied the topic: Help working out Beetle diagram question

Yes, they use the same booklet for all exams and all subjects, RPL, PPL and CPL
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