CRP-5's for ATPL Nav

[JohnnyPharm]

Do we really have to use a CRP-5 in the exams. I have an old Jeppesen one that seems to do the trick, however does not have the specific gravity section on it. Also I don't know if anything different will come up further on in the course that requires the CRP-5. I know in the scheme of things its only £50, but it is still £50 to get one.

Anyone else done the Nav exams with a Jeppesen Wizz Wheel?

[FlyingForFun]

Johnny,

The problem is that the flight computers are not completely accurate. The examiners work out the answers using the CRP-5, so any inaccuracies in the CRP-5 will be reproduced in their answers.

Although I don't know this for sure, there are plenty of people who believe that if you use another computer, you will get different inaccuracies in your answer - and that there are some questions where the options are so close to each other that this may cause you to choose a different answer to the one the examiner wants you to choose.

Having said that, though, you won't be the only person to use a different computer.... and other pepole who use different computers seem to get by ok.

Have you tried searching E-bay for a cheap second-hand CRP-5?

FFF
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[Send Clowns]

You will need to use the specific gravity section, certainly in the General Navigation exam. I have not check a Jeppesen flight computer, but certainly the AFE larger version computer, the ARC-2, does not get the same answer as the CRP-5 to questions involving compressibility. As FFF says the CRP-5 is used by the examiners to find the "correct" answer. Does your Jepp even take into account compressibility? Mine doesn't.

It is actually about £72 new, but the CRP-5 is the best flight computer I own.

Send Clowns
Gen Nav instructor, BCFT

[six-sixty]

I did nav with Bristol, and in the brushup course all the debriefs from the mock tests are done on their demonstrator massive CRP-5. People (like me) who had same and had problems could follow it through, but one guy had a different machine AND was having problems, thus making life unecessarily hard for himself in my opinion.

May be something to bear in mind if your course follows a similar format.

You can always ceremonially burn the damn thing afterwards (I did learn to hate mine):E

[Bubble]

You may know that in Spain for example they do use a Jeppessen CR-3 for the ATPL exams, so I don´t know how good or bad that could be or if it would make any difference at the exams.

[High Wing Drifter]

Also, try and avoid getting a CRP with one of them fangled "wind arms." A pain in the posterior so I'm told.

[BIG MISTER]

The Bristol CRP 5 is indeed massive ......but size isnt everything !

Mind you the 'Devil' in me did wonder if I would be allowed in the CAA ATPL exams with the Bristol version of the CRP 5 ! ! ! !

To answer our friends original question.....The bottom line is that they use the CRP 5 for the questions. Its an exspensive bit of kit and maybe you will buy a 'plastic brain' Nav computer afterwards and never use it again......

But it would be a shame to miss the exam by say 2 questions which the CRP 5 could have answered....£75 for the CRP 5 and £55 for another go at the exam ????

Good luck whatever mate ! ! !

:D

[Tinstaafl]

A CRP5 is not necessary **IF** you're up to speed with your alternative AND it's suitable for ATPL level problems eg Jepp CR5 or whatever but not Kane E6B. Bear in mind that UK instructors *tend* to only be familiar with the CRP5 so you'll have limited access to assistance if you have problems using your alternative. This is an important consideration!

The larger the whiz wheel the more accurate the answers will be. It's a slide rule after all, and increasing size allows finer discrimination of slide position. I've done Oz, USA & UK ATPLs with a Jepp CR5 (the smallest & therefore least accurate) and my answers in the UK have always been comfortably within the median of those using CRPs.

The argument about 'examiners derived the answer on xyz type etc...' isn't an issue if you are precise with your use of your alternative. The question's answer options must allow for the limits of accuracy of the tool used to derive the answer. If your tool is within that range then you'll be at least as accurate as that other type. My experience from a group of us using CRs vs the rest using CRP5s has been that CR types are generally more accurate than the CRP5, producing a tighter cluster of answers around the median of CRP5 answers.

Some problems required fewer steps with a CR type which was a nice bonus.

[ChocksAwayUK]

Do any of you nav computer historians know if there have been any changes to the CRP-5 in recent years? I'm using my dad's 1968 vintage model and while it appears to be the same as recent ones i wonder whether i will be at any disadvantage in my exams in November.