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Failed CPL performance

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Bosi72 replied the topic: Failed CPL performance

>Another accuracy thing I seem to
>struggle with is the ASA-E6B-CIRC
>calculator wind calc accuracy. I never
> quite get the exact headwind or
>crosswind component that the
>answer has.

I use Ersa/Aip conversion page for hw/xw calculation. A bit more precise than e6b and I think thats what they expect in results.

E6b is great tool when flying (probably not anymore with ipads), but in the exam, calculator has priority.

Bob Tait Navigation Workbook is good book for practice. Error of one or two knotts or degrees is ok.

Also when rounding, regardless of question (fuel, wind, track, w&b, pnr/etp,..), I always use two decimals in every calculation, then round the final result at the very end.

With pnr/etp never use 2xTAS, always use GSo+GSh.

Hope this helps
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  • John.Heddles
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John.Heddles replied the topic: Failed CPL performance

If I may offer some further comments.

I use Ersa/Aip conversion page for hw/xw calculation. A bit more precise than e6b and I think thats what they expect in results.

Really shouldn't be the case - they both do exactly the same thing and, with a bit of care, using the whizz wheel will give you fine answers.

E6b is great tool when flying (probably not anymore with ipads), but in the exam, calculator has priority.

I guess quite true about the ipads, but, again with a little bit of care in execution, the whizz wheel will give you a final answer in the same region of practical accuracy as you get with the electronic gadget.

Also when rounding, regardless of question (fuel, wind, track, w&b, pnr/etp,..), I always use two decimals in every calculation, then round the final result at the very end.

My suggestion is just run with whatever accuracy your electronic gadget has in the background. These days, that is umpteen decimals. The secret is to make use of rolling calculations and the accumulator so that you aren't playing around with writing and entering intermediate numbers.

With pnr/etp never use 2xTAS, always use GSo+GSh.

Not really the case. The approximation breaks down at high drift angles. If the wind is light and/or more or less along track, the difference is small. Having said that, I concur with B - if you have the G/S values, prefer to use them anyway.

For A, again, we can't really help you unless we can see what you are doing. Suggest you photograph some whizz wheel settings for several examples and post them - if you are having any problems, we will see them very quickly.

When it comes to the whizz wheel, it's like anything where you exercise a skill - lots of practice and you get good at it. As Charles Goren replied, years ago, when a bridge player observed that he had incredibly good luck at the table - "the more I practice, the luckier I get !". Actually, that aphorism has been ascribed to any of many celebrities but you probably get the gist of what I am suggesting ?

Engineering specialist in aircraft performance and weight control.
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Airspeed replied the topic: Failed CPL performance

Thanks guys.

I think I've gotten better at accurately doing the P chart questions. The last exam I had didn't even have any linear chart questions. I think those are the trickiest.

The only prob I have with accuracy on the wizz wheel is finding ETAS. IE if the cross wind is 22 or 23, do I take the drift angle closest to 22 or 23? Sometimes seems to work out, but I'm scared about CASA's accuracy requirement, if the incorrect drift angle of 1 or 2 degrees throws the answer out completely.

I have my next Attempt on Sat. If I come up with an example again, I'll post it.

For an example of the PPE stuff. Have a look at my question regarding PNR. I think their way of calculating Variable reserves is incorrect.

Forum PNR Question here
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John.Heddles replied the topic: Failed CPL performance

The last exam I had didn't even have any linear chart questions.

. but that format is endemic in the Industry so you really do need to be competent in its use. At day's end, it is pretty well the same as the DCA P-chart format.

The only prob I have with accuracy on the wizz wheel is finding ETAS.

I ran up a bit of a burst on ETAS in the following thread, which might be of use to you for background ..

bobtait.com.au/forum/general-enquiries/6...by-using-a-cr3#13063

if the cross wind is 22 or 23, do I take the drift angle closest to 22 or 23?

Just take the closer. Keep in mind that you are just running a multiplication (per the previous link) using the computer's underlying slide rule capabilities. The difference isn't going to make a difference in the realm of sheep stations.

Sometimes seems to work out, but I'm scared about CASA's accuracy requirement, if the incorrect drift angle of 1 or 2 degrees throws the answer out completely.

To give you some real guidance, we need to see what you are doing. I can only suggest that you post some specific examples for comment.

For an example of the PPE stuff.

Better to start with the original thing. Are you able to post a picture of the original question for comment ?

Engineering specialist in aircraft performance and weight control.
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Airspeed replied the topic: Failed CPL performance

Are you able to post a picture of the original question for comment

The original question is in one of my followup comments in that thread.
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John.Heddles replied the topic: Failed CPL performance

Comments added to the other thread cited.

Engineering specialist in aircraft performance and weight control.
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