PPL Confuser - Another Discrepancy [Archive]

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skyhighbird

11th Apr 2009, 08:05

Guys,

A while back I wrote a post regarding how the AFE (CAA Lasors recommended) practice test was nothing like the questions in the Confuser. But the confuser is as close to the real thing as possible. Laughable.

Anyway, that was for Air Law and I am happy to say I passed it. NOw I am doing Meteorology anf lo and behold, I see another discrepancy - not just in the way they ask the questions but the answer. So here is the example:

Q23

At 1400z, the surface wind was 22025kt. The likely Wind velocity at 2000ft agl would be:

a)26040
b)24035
c)22020
d)23030

I answered A. Because according to Pratt's AFE book, wind veers 30' and windspeed 50%.

So 220+30=250. And 25kt+50% = 37.5kt.

So now we have a problem. The answer (according to the assumptions in AFE) is slap bang in the middle of answer A)26040 and B)24035. So I rounded up.

However the answer is B. Not because of rounding down but becasue the assumption is that wind veers 25' giving a direction of 245'.

So naturally the Confuser answer should be B) 24035.

So guys. What should I do? Should I go with the 25' assumption or keep with Pratt's 30' assumption? Or should I just chuck away all my PPL books that cost me around a hundred quid and just learn the Confuser because the AFE books give "wrong" information?

Whats the point of putting your heart and soul into learning principles and facts only to find out that the questions are based on different principoles and facts.

gordon field

11th Apr 2009, 08:51

You may have problems with your wind but you also have problems over use of decent language, it is not clever, professional or necessary to use such words.

skyhighbird

11th Apr 2009, 09:04

I guess my wording was used to illustrate yet again another failing in the literature that has been "recommended" for PPL exams.

I thank you for your opinion and apologise if I caused offence.

Can you also contribute as to whether I use 25' or 30' when it comes to the "real"thing.

99jolegg

11th Apr 2009, 11:42

Yes, approaching the ground the wind backs 30 degrees and decreases by 50%...going the other way, leaving the air affected by friction of the earth and the wind veers 30 degrees and increases in speed by 50%. I've seen this written in a few places; never seen 25 degrees mentioned.

skyhighbird

11th Apr 2009, 18:04

So what is the figure guys (thanks for the insults by the way).

In the exam do I use 25 degrees or 30 degrees?

But I will move this to the other forum if you think that is best.

skyhighbird

11th Apr 2009, 18:16

tigermagicjohn

11th Apr 2009, 19:19

I think it's about using practical common sense and LOGIC, there will never be a Standard day.

If you use answer A, it will mean the wind veers 40 degrees! Where you have read that the wind would be 40 degrees?

Also note the question, "LIKELY" - again does not mean it is an exact answer, but you need take the answer most likely closest to what you have read and learnt.

The wind speed you chose 40 kts, which is more then 50% of 25kts, so with what logic would you round it up, when your calculations should be 50%, 40 kts would be 62.5%!

The closest to standard would be the most likely outcome!

Keith.Williams.

11th Apr 2009, 19:31

Don't expect any book to be 100% correct.

Every book that I have ever read and every book that I have ever written has contained some errors (and I don't mean just typing errors).

The AFE statement is the conventional wisdom on this subject.

The author of the PPL Confuser probably wrote his explanation to fit what was then the CAA answer to the exam question.

The question has since been updated. Neither the 30 degrees nor the 25 degrees nor the 50% speed change argument will get you exactly the CAA answer. But they will all get you an answer that is closer to the CAA answer than it is to any of the other options.