CRP5 Questions

[Base leg]

- Working out true altitude is not a problem, and more useful I think- but this has me confused.....any help would be appreciated.
(You are given pressure alt. or true alt. a QNH and SAT)

[jarjam]

CRP5 IS SHORT FOR CRAP 5. JUST DONE THE JAA EXAMS MYSELF ANSWERS ARE NOT VERY ACCURATE WHEN USING THE '5' SO WE WERE TOLD TO JUST TO USE ISA DEVIATION MULTIPLYED BY 120.
FOR TRUE ALT CALCS TRY USING ISA DEVIATION MULTIPLY BY 4 {CONSTANT) THEN MULTIPLY BY HEIGHT IN THOUSANDS.
E.G -5 MULTIPLY BY 4 MULTIPLY BY 12(12000)
GIVES A MUCH MORE ACCURATE ANSWER AND ALL OUR CHAPS ARE PASSING NAV SO GIVE IT A GO.

[pipergirl]

if anyone has a secondhand(in good nick) crp5 computer that they would like to sell at a good price, please email me...
cheers

[QNH1013]

Ummm, the bosses here don't like these kind of posts unfortunately.

But anyway, I've sent you an e-mail regarding this :D

Have fun training.

[Backontrack]

Help me out guys/gals

This is my first post. I am a PPL student. 30 odd hours, just really embarking upon Navigation.

Did your instructors really explain the Nav computer to you?? Mine has not, and frankly I am finding it highly confusing!

Does anyone have any hints and tips to get me on the right track? How did you become accomplished with your CRP5?

Thanks

[mad_jock]

h'mm i must admit i didn't completely understand the beast until i met gen nav in the ATPL's. And worked my way through the monkey see, monkey do chapters in the oxford notes

Which bit do you have problems with?

Is it the wind triangles or the slide rule bit on the other side?

MJ

[tacpot]

No, my instructors didn't go out of their way to explain how to use the nav computer. But I found it relatively straight forwards just by following the instructions in the booklet that came with it. The AFE/J. Pratt PPL syllabus books have further instructions on the basics in them.

The main thing seems to be practise. The more you use it, the better you get at using it. The other thing that still takes me a while is doing the rough calculations that give you an idea of the scale of the answer that you are expecting.

I guess it seems anachronistic in this day of 'real' <img src="wink.gif" border="0"> computers to have to use a ciruclar slide rule, but as others will point out, the batteries can never fail in a CRP-5. But on the other hand, a real computer will tell you the answer without having to pre-calculate a rough answer!

I assume you are having trouble with the slide rule bit and not the wind calcultions. If you are having trouble with the wind calculations, make sure you understand the theory behind what you are trying to acheive and then just practise, practise, practise.

[ 07 January 2002: Message edited by: tacpot ]</p>

[Tinstaafl]

[quote]...a real computer will tell you the answer without having to pre-calculate a rough answer! <hr></blockquote>

Not true! Electronic computing devices are not infallible. Apart from failures of the device there is also the 'garbage in - garbage out' problem.

Unless you have some idea of what the answer should be, how will you know when the electronic brain gets it wrong? And it will get it wrong.

As for using a circular slide rule, only practice will enable the user to become adept. I find some problems can be solved quicker using a whiz wheel than a calculator.

If one type of whiz wheel is awkward, try using a different type eg from the 'slide' type to a 'CR' circular type. The CR5 from Jeppessen is my favourite.

[ 08 January 2002: Message edited by: Tinstaafl ]</p>

[Send Clowns]

Backon

If you have any specific queries feel free to email me. It is hard to teach the whole thing remotely by internet! I am a ground instructor, formerly of General Nav for the now dormant SFT. Alternatively if you're near Bournemouth anytime soon I am happy to teach you the rapid and accurate use of this wonderful and powerful calculating device, in exchange for a couple of pints.

And Tacpot, if you're well-taught then you should have a rough answer in your head already! :)

[Blackshirt]

I was taught how to use the ****ty-Five by Mr. Send Clowns, and confirm that it ayn't hard to use once you've been shown how properly.

Hot Tip alluded to already: take an educated guess as to the answer BEFORE you pick up yer CRP-5, that way you'll know immediately if final answer you get is bollocks or not.

[ 08 January 2002: Message edited by: Blackshirt ]</p>

[FlyingForFun]

I seem to remember that reading the Trevor Thom book on Navigation or Flight Planning, I forget which, was what finally got me to understand it.

I'd dig the books out to find out exactly which book it was (and it wasnn't some other book completely!) but my bookshelf is half way across the world at the moment, so apologies if I'm wrong and there's nothing helpful in Thom!

FFF
---------

[Paul Hickley]

Backontrack,

Basically, there are 4 types of operation that the CRP5 does for you.

1. Multiplication and Division and Conversions, just like any slide rule. I agree, for these, you are probably better off with an electronic calculator.

2. Distance, Speed and Time (and fuel-flow calculations). You can do these with a calculator, but it's actually quicker with a CRP5, once you get good at it. With a question like "You are doing 220 knots groundspeed, so how long will it take you to cover 57 nautical miles?", if you use a calculator, you get the answer in hours. You then need to multiply it by 60. By the time you've done that, you could have already had the answer on the CRP5, in terms of minutes, which is what you want, not hours. On the other hand, if the question is "Your groundspeed is 320 knots, so how far will you travel in 13 minutes?", then you need to divide, not multiply, by 60. With a calculator, decisions as to which way round to do the calculation, and slight loss of speed. No such problem with the CRP5. With that big black triangle on the inner scale, you work in base 60. It gives you the answer in the form you need it.

3 TAS and Altitude Calculations. To calculate these by numerical methods on an electronic calculator requires specialist formulae, which are too complicated for everyday use - especially TAS from FL and temp, and Compressibility correction. The CRP5 solves them simply and accurately.

4 Wind Calculations - the relationship between Heading, Track, Drift, TAS, and Groundspeed. These are vector problems and would be too complicated on a normal programmable scientific calculator. You have been able to get specialist aviation calculators with the formulae already programmed for years, but these have never really caught on because the presentation on the CRP5 wind face, as well as solving the numerical problem, gives you an instant intuitive picture as to whether the wind is giving you mainly head/tailwind component or mainly crosswind, and a visual picture of whether it's head or tail and which direction the drift is in.

Three other observations:

Firstly, if your instructor hasn't explained it to you, he's not doing his job properly. Ask him. You may find he doesn't know it himself.

Secondly, the little book that comes with the CRP5 is excellent! You can use it to teach yourself very easily, if you want to.

Finally, the Oxford/Pooley CRP5 Computer Based Training (CBT) CDROM will be available in February. You can get it from Pooley's. It is so clear in its explanation. In the meantime, if you want to, you can get the CRP1 CBT CDROM. It's pretty similar to the CRP5, but without the same number of facilities.

All the best,

Paul

[ 08 January 2002: Message edited by: Paul Hickley, Gen Nav Spec, Oxford ]

[ 08 January 2002: Message edited by: Paul Hickley, Gen Nav Spec, Oxford ]

[ 08 January 2002: Message edited by: Paul Hickley, Gen Nav Spec, Oxford ]</p>

[Rowley]

I was under the impression we are not allowed to use calculators in the JAR Eaxma (PPL/ATPL)

Is this correct???

My instructor explained a little bit, but i got most of my info from the handbook that you get with it and also from the Jeremy Pratt Nav book!!

[prob30]

You can take your CRP-5 or simillar into any exam in any subject. You can also take a non programmable calculator too.

Only way to master the whizz wheel is to use it every day. U have too be damn fast in the atpl nav exam cos time is tight.

AS paul said the wee book is escellent

[Rowley]

Well that just rips it!!!!! <img src="mad.gif" border="0"> <img src="mad.gif" border="0"> <img src="mad.gif" border="0">


My flying school told me i wasnt allowed a calculator for the nav exam!! I had to do all my working out on my wizz wheel!

Still passed though!

:) <img src="wink.gif" border="0"> <img src="cool.gif" border="0"> :)

[Quidditch Captain]

The Trevor Thom Navigation book explains the CRP in great detail and is very understandable.
Also as Paul says, the little book which comes with the CRP-5 is also worth working through.
Also as previously stated in another post the Oxford General Nav ATPL notes go through the CRP-5 in great detail but its probably overkill to buy these if you are 30 hours into PPL.
Good luck

[Send Clowns]

Paul may correct me if I'm wrong, but no electronic calculator is permitted in any of the PPL exams. The CAA has always been concerned by the slack control of exam sittings shown by some small flying schools/clubs, so maybe that is why some have been allowed. Non-programmable electronic calculators (not electronic flight computers!) are however permitted in all CPL/ATPL exams.

[Backontrack]

Thanks to everyone for their replies. It helps knowing your no the only ones struggling sometinmes.

I shall attack the Nav book and give it another go.......just hit a brick wall I think.

cheers

[Tee]

Backontrack,

Some Instructors teach the "wind up" method of using the whizzwheel and some teach the "wind down" method; if you intend to progress to CPL/ATPL, start using the appropriate method from the outset. I was taught one for the PPL and had great difficulty getting to grips with the other for the ATPLs.

[ 08 January 2002: Message edited by: Tee ]</p>

[Paul Hickley]

Tee,

Couldn't agree more!!!!!!!

'Wind up' is suitable only for PPLs, because they won't have to wind find or work out track from heading. But if you're going to be a professional you must use 'wind down'. It's the only way that's compatible with 'heading from track', 'track from heading', and 'wind-finding'. PPLs only have to do the first. However, if you want to pass these pesky JAA ATPL exams you have to be able to do all three. You have to do it 'wind down'.

Sorry about all the bold face. I don't shout in my lessons - well, not often, anyway. But the point is important.

All the best,

Paul

[ 08 January 2002: Message edited by: Paul Hickley, Gen Nav Spec, Oxford ]</p>

[Tinstaafl]

Or use a CR circular type & never be bothered by the 'wind up' or 'wind down' carry on... <img src="smile.gif" border="0">

Yeah, yeah. I admit I'm biased. But in fairness I did Oz PPL & CPL all on a slide type (calculators only allowed in the CPL Performance & Operation subject), then Oz IR, Oz/USA/UK ATPLs on a Jeppessen CR5. In 10 years instructing I taught with both types & my vote is definitely to the CR.

NB. I still have & will keep the Kane slide type. Accurate & durable - if you want to put up with the bulk of a slide & the weight of all its thick aluminium!

[Charlie Foxtrot India]

The circular ones, aka "chick magnets", are designed for males to be prominantly placed in the top left hand pocket of your pilot shirt, to subtly let the female world know "I Am A Pilot"(in case they thought the epaulettes meant you were a prison officer or bus driver)

I had heard a rumour that these could also be used for navigation calculations in an emergency.

IMHO When it comes to accurate nav calculations, you can't beat the CRP-5. Does anyone know where I can get spare parts for one in Australia as mine is falling to bits after 14 years.

Wind dot down...put your track on the top...draw vertical line through wind dot...put grommit over TAS...turn line until it parallels a drift line...heading is on the top, and g/s under the dot.

BTW Tinny, candidates can take a non-programmable electronic calculator into the Aus PPL cyberexam.

[john_tullamarine]

I'm not entirely sure what is meant by the terms "wind up" and "wind down" but I presume it refers to the orientation of the wind vector on the prayer wheel's vector grid as the problem is solved by the pilot.

Do keep in mind that the little pocket Jepp style calculator and the traditional EB6 style use different triangles for the vector resolution and that has a material outcome for the different manner in which each is used.

Unless someone has come up with yet another implementation of the vector solution (and I admit to not having kept pace with the calculator marketplace in recent years), I am only aware of three; the two common ones mentioned above and an interesting Aristo calculator which I used briefly many years ago.

I am totally perplexed by the reference to the PPL doing it differently to the CPL/ATPL pilot. Either it is done correctly, or it is done incorrectly. I look forward to being enlightened on this one ....

And, Backontrack, do be very aware that the great majority of people have a very, very limited knowledge of the details which go into prayer wheel design ... it all tends to stop at monkey see, monkey do. I can recall the odd ground/flying school instructors telling me some of the most imaginatively incorrect ways in which to use the gadget ....

[ 09 January 2002: Message edited by: john_tullamarine ]</p>

[Send Clowns]

Wind up and down are both mathematically correct methods, achieving the same result. Wind up is initially slightly simpler, but in truth even given the errors some students initially make wind down is the best way. The errors are small enough for PPL purposes, and I have had students at ATPL who had great trouble converting, and kept making mistakes on the wind-down method.

[Tinstaafl]

Hi CFI,

Yes, I know calculators are allowed now. Once upon a time in the dim, dark mists of time they weren't...

[john_tullamarine]

Send Clowns,

Your response is not particularly useful.

A quick net search has not found me any references to the "wind up" and "wind down" techniques.

Could I trouble someone to give me, preferably, net references, or else text references so that I can familiarise myself with what the conversation specifics are about ?

[ 10 January 2002: Message edited by: john_tullamarine ]</p>

[DesiPilot]

Dear Paul,

Please correct me if I am wrong but I have always used the "Wind up" method. I do consider myself as professional as my fellow pilots. I have passed Navigation exams in India, UK and in USA and had no problems what so ever.
I did my NAVs with Bristol and I was also told that I will not be able to do all the calculations if I use wind up method. I couldnt get my head around wind low method so I used wind up and I had no problem and got the results every single time.
I think it all depends on which way you were taught and how comfortable you feel using it.

<img src="smile.gif" border="0"> Jatin

[ 10 January 2002: Message edited by: DesiPilot ]</p>

[Paul Hickley]

To John Tullamarine:

Let me explain 'wind up' by use of an example. You are in a PA28, TAS = 100 knots. You want to fly a track of 072 and the wind is 315/20.

OK, start off in the usual way, by putting the wind on. Bring 315 on the inner wheel up against the 12 o'clock position, ie, against the heading index. But instead of plotting your 20 knots downwards, ie, in the 6 o'clock direction, plot it upwards, towards 12 o'clock.

Now rotate the desired track, 072, to the 12 o'clock position. Move the slide so that the wind mark you have made appears against 100 knots.

This tells you immediately, with no juggling to balance the drift, that the required heading is 10 degrees left of the track, ie, you need to fly 062. Your groundspeed will be the figure under the centre mark, ie, 108 knots.

Everything is the 'wrong' way round if you are used to the normal way of operating. The heading marker is indicating your track and the wind point is on the TAS, with the groundspeed under the centre dot. But it does have the advantage of being a one-shot operation. No fiddling to adjust the drift.

Many flying schools , especially in the USA, teach it this way to their PPL students, who find balancing the drift too difficult. If all you are ever going to do is, given the desired track, find heading to fly, it is easier. But if you are going to do either of the other operations, it gets extremely confusing.

I don't teach it, and I don't recommend it. But you are entitled to a decent explanation. As for the rest of you out there, don't use it if you want to become an ATPL.

To Desipilot:

Do whatever works for you, as long as you get the right results. I think you're past the student stage by now, anyway. But if, as a student, you use a non-standard method after being taught the correct one, don't expect the instructor to bust a gut in helping you out if you encounter difficulties with it.

All the best,

Paul

[Foyl]

JT, I can't follow the method either, but going through the method described and Tinstaffl's comments I think it's because I've always used the circular whiz wheel (as described by CFI as the "look at me I'm a pilot" model :) ), as opposed to the one I've seen in the Trevor Thom books. Is that the same one you use?

Can someone confirm that this is the case?

[john_tullamarine]

Paul,

Thanks for the clarification...

I found a picture of the CRP5 on a web site and it appears to be a fairly stock standard sort of E6B/Dalton ? Am I correct in that assessment ? If not, I would appreciate a 5 second heads up on the differences.

My initial confusion related to the "wind up/down" terminology which I hadn't come across before and the suggestion that one could use the calculator in more than one way to solve the vector problem graphically.

What then confused me greatly was the suggestion by another poster that the two methods are mathematically equivalent, a claim which appears to be arrant nonsense.

IF (and I emphasise IF) the gadget is a simple E6B then it would appear to me that to use "wind up" is graphically flawed (ie trignometrically incorrect) although, as the consequent error is negligible for small drift angles, the answer is acceptable for practical purposes. Even for largish drift angles the errors are not so great that they would cause a major problem in flight.

But this is hardly justification for using a flawed method which is intellectually confusing, especially without making it clear to the student that this is the case. Add to this the problem with pilots often swapping to the little Jepp wheels when they get onto faster equipment and the opportunity for needless confusion becomes a worry.

Surely a basic tenet of sound instruction is neither to teach nor permit the student to apply incorrect techniques, whether in the classroom or in the aircraft, useful simplifications and shortcuts notwithstanding. The extra minute or two necessary to ensure that the student understood what he/she is doing with regard to the vector solution would far outweigh the very questionable gains to be had using a flawed technique which then has to be unlearned later on.

Quite some years ago I taught CPL/ATPL classroom theory for around 15 years or so and NOT ONCE out of quite a few hundred pilots can I recall a student having more than trivial difficulty learning and doing the exercise the graphically correct way.

Can someone tell me .....

(a) have I missed some vital underlying lemma here ?

(b) what purposeful advantage is there in using a flawed technique when the correct approach only takes a moment or two longer, makes intellectual sense, and doesn't have to be unlearned next month because it is wrong and doesn't work to sufficient accuracy ?

Perhaps I have yet another piece of quaint folklore to add to my list of innovative ways of using the prayer wheel.

Foyl, I use either style of wheel according to whichever I pick up in my little hand first to solve the immediate problem. It doesn't matter.. if the same data is built into the wheel's design then either will give the same answer if used correctly. Many of the E6B machines don't have any compressibility data so, in that case and for high speed aircraft, the little Jepps are more useful.

[Paul Hickley]

Foyl,

Even if you use the circular sort, you can still use them either 'wind-up- or -wind-down'. Try my example the normal way, then reverse the wind direction to 135, and you will get your triangle of velocities without any drift-juggling. Not that I recommend it - just to show that the type without the slide makes no difference to the argument.

John Tullamarine,

Yes, the CRP5 is like a Dalton or Jeppesen EB6. It has a rectangular slide, with a high-speed and low-speed side. The slide rule has a few more facilities (compressiblity slide-rule, not a table, and calculation of True Altitude or Density Altitude from Pressure Altitude and Temp), but the Wind Face works on exactly the same principle.

Send Clowns is perfectly correct, the 2 methods are mathematically equivalent. You are not changing the geometry of the triangle of velocities by plotting upwind. You are simply displacing the axis in which you plot it on the face of the computer. The triangles are identical.

As for what is the 'correct' way to do it, I think it's horses for courses. I've already said I don't teach 'wind-up' and don't encourage its use. But the GA situation in the USA is virtually unique. Many people who have lots of surplus wealth want a relaxing week-end hobby. If the flying clubs make it all too difficult, the same people will go jet-skiing, powerboat racing or snow-boarding instead. These guys are not going to become ATPLs. Provided that safety is not compromised, it's good that they enjoy flying. Lighten up a little.

All the best,

Paul

[ 11 January 2002: Message edited by: Paul Hickley, Gen Nav Spec, Oxford ]

[ 11 January 2002: Message edited by: Paul Hickley, Gen Nav Spec, Oxford ]

[ 11 January 2002: Message edited by: Paul Hickley, Gen Nav Spec, Oxford ]</p>

[Send Clowns]

Apologies J_T, I was merely trying to reassure you that both methods give the correct result for problems of heading and groundspeed.

It is very hard to teach CRP-5 in text, I would always recommend you get someone to teach face to face, and check what you are doing. If your own instructor is unable and unwilling, and none of your other club instructors will help, then you might do better at another club! It is part of an instructor's job to teach these things, and it is important, especially if you plan ever to become a commercial pilot, that you can use this instrument quickly and accurately.

[john_tullamarine]

You both seem very sure of your ground.. perhaps I had best go away and do some trig on the matter before I consider my position ?

[john_tullamarine]

Several cups of coffee and sheets of paper later ....

Ooohhhh dear ...

Perhaps the ports which accompanied the coffee consumption had something to do with it but now it is apparent that I was guilty of contemplating a subject over a cup of coffee without drawing a sketch and doing some sums ... how often do we all exhort our students to "draw a piccy" ?

As a result, I permitted the engagement of my mouth (keyboard, if you will) whilst the brain, quite clearly, was doing something else. (Quietly goes away and tears up degree due to obvious and gross incompetence ...).


Please do let me edit/correct my previous post ...


The statement that the wind up and wind down methods for the E6B style of instrument are identical is perfectly correct and, in fact, it is the one and the same vector triangle ONLY which is being "drawn" over the slide fanlines regardless of which method is used .. not even a matter of different triangles at all.

This is quite easily seen by drawing the vector picture on paper using correct bearings and scale on a fan and radii background and then considering what is being done with the instrument using first one, then the alternative methods. Either way .. one triangle ... so the same answer ... no error.

For me, though, it is very easily confusing if one is concentrating on the instrument (which is, after all, the window through which we see part of the complete vector triangle).

For those who are similarly prone to confusion, consider that you are also "moving" the entire instrument (as a window) over the larger background grid toward the track vector. Not at all easy to sort out in the mind without a sketch to aid orientation.

I haven't looked at the solution on the little Jepp calculator so I offer no comment in respect of that instrument. When next I have one in hand and a few minutes to spare I will contemplate the problem once more.


My humblest and most obsequious apologies, both to Paul Hickley and Send Clowns ...


The main thrust of my concern as an instructor still stands. I have no problem with using any method that produces a good answer in practice. However, for the instruction side of things, to introduce needless intellectual complexity when a student needs just the opposite .. appears to me to be counterproductive.

The student is best placed to understand what he/she is doing if he/she can see the relationship beween the instrument actions and the base vector solution and this is one reason why it is easier for most people to follow the rationale behind the E6B rather than the little Jepp although I hasten to add that both are fine instruments.

It is for this reason that I would avoid the use of a method ("wind up" on the E6B) which

(a) is very confusing, intellectually, when viewed against the basic solution.

(b) really offers a negligible increase in ease of instrument use, although that is, admittedly, just my opinion. I reiterate my earlier statement that I have never had a student who had other than the usual trivial difficulties in coming to grips with the traditional method of using the instrument. If there is an advantage in the alternative method, then I suspect that it is more imagined than real.

It would appear that Paul and I agree on this general point of view.

Rather than folklore, I have learnt something new ... and that can only be a good thing ...

Have I lightened up sufficiently for you, Paul ?

best regards ...

[ 12 January 2002: Message edited by: john_tullamarine ]</p>

[bluskis]

The wind correction rotation needed on the CRP type computer often confused me in the early days. I eventually found that a double check of my result was useful. That check was, am I leaning (heading) into wind,relative to intended track.

[TheDrop]

Paul, and others,

Please answer this one for me:

Is there a requirement for a slide/circular computer that can calculate compressibility - for the JAA ATPL exams ?

In other words, the "Pooleys CRP-1", is it sufficient for the ATPL exams, knowing it can handle neither high speeds nor compressibility ?

Also, a reference to where it can be found as to what calculators are allowed to the exams, would be welcome. (Electronic, non-programmamble OK ?)

TD

[TheDrop]

By the way, when I was reading this thread and saw "wind up" - I couldn't understand why you got so wound up about wind up. I was reading "wind up" as in overreacting to something !

[Foyl]

Thanks JT & PH, woke up when I read it through properly - with brain engaged this time... <img src="rolleyes.gif" border="0"> :)

[Paul Hickley]

I can't believe this - a flaming suitcase to the left of the thread showing hot interest in the topic - on the CRP5!!

To The Drop:

The JAA ATPL Gen Nav, Flight Planning and Instruments exams all require you to be able to calculate TAS from FL and OAT for cases above 300 knots. If your flight computor doesn't have a compressibility slide-rule or table, then you are allowed to take a single-sheet compressibility correction table in with you to the exam. If an Oxford student already has a flight computer without compressibility and doesn't want to buy a CRP5 when he starts the course, we issue him with the compressibility correction table.

You are also required to solve triangle of velocity problems at typical flight speeds of modern jet airliners, ie, TAS of about 420 to 490 knots. If you haven't got a high-speed slide, it will slow you up. You can solve the problem by halving the TAS and the Windspeed, solving for that case, and doubling the groundspeed you find at the end of the calculation. The drift is correct. I really wouldn't recommend it, though. Speed is everything, especially in the Gen Nav exam - almost everyone finds it tight for time.

If you're going to do ATPL, you need a proper flight computer to give yourself a fighting chance. Take the view that it's a long-term investment - if you get your licence, you will probably be flying high-speed aircraft. And if you look after it properly, it will last you a lifetime.

As for electronic calculators, you can use any non-programmable sort. Get a reasonable scientific one - you must have sines, cosines, tangent, logs, and powers. You can't use specialist aviation electronic calculators, such as the Jeppesen Electronic E6B.

I'll see if I can find the reference quoting the calculator regulations at work on Monday. I haven't got it at home. But what I've told you above is correct.

All the best,

Paul

[TheDrop]

Thank you, Paul, I will see if I can get that compressibility sheet. The wind side is OK, it has the fast side as well ...

TD

[HelenD]

Looks like I taught myself the wrong method, would it be worth me learning the wind down method before I get to do the navigation section of my PPL? I passed the nav exam using the wind up method having spent 3 days with the Thom manual, map, CRP-5 and PPL confuser.

[Paul Hickley]

SothernHighFlyer,

I wouldn't bother to change at this stage until your PPL is complete. Pass the Nav Test using the method you understand.

If you decide to progress beyond PPL, change to 'wind down'.


The Drop,

We can't find the quoted reference. We are wondering if we got the information from the CAA through an email or letter. But, as I said, I can assure you that what I said was correct. We issue the Casio fx-85WA to our students, but any inexpensive non-programmable scientific calculator will do.

Paul

[ 15 January 2002: Message edited by: Paul Hickley, Gen Nav Spec, Oxford ]

[ 15 January 2002: Message edited by: Paul Hickley, Gen Nav Spec, Oxford ]</p>

[HelenD]

Thanks just hope my instructor can cope with the wind up method when we do the navigation bit. Even if I wanted to I very much doubt the CAA would let me do much more, though I do plan to add an IMC rating eventually. If the APTL ground exams were cheaper I would consider doing them as the PPL ones were not enough of a challange.

[TheDrop]

Thanks, Paul ...

TD

[john_tullamarine]

May I follow up on my previous post now that I have had time to play with the two devices.

(a) first I must again 'fess up to the arrogance of my ill-considered first post .. it would have been far better had I done the homework then (before commenting) rather than now .... c'est la vie ...

(b) DesiPilot was quite justified in being a little concerned and, while Paul Hickley and Send Clowns clearly understand the following, it may be of use to other readers to review the salient matters under discussion. It confused me to start with .. and I guess that there will be others in the same boat ...

My comments relate to the conventional Dalton and CR styles of computer in respect of the typical navigation solutions mentioned below. (I loosely refer to "vectors" for convenience .. not quite rigorous .. but convenient shorthand for a "line drawn to a scale speed and plotted at correct azimuth").

Dalton (E6B)

The Dalton provides a means to plot the W/V end of the navigation vector solution (navigation triangle).

The picture we get is the same as if we plotted the triangle directly onto a sheet of graph paper. The easiest way to think of it is to consider the instrument "floating" above the graph paper .. we look through the rose to obtain a view of the grid and the triangle, much in the same way as MS Windows provides a screen through which to look upon the "desktop" beneath.

The conventional solution requires that the centre of the compass rose viewer be located over the intersection of the TAS/HDG and W/V vectors. For this approach, when plotting the W/V vector, it is drawn "wind down" from the centre point.

However, because of the way the grid is drawn (r-theta, azimuth-range, angle-distance .. whatever descriptive term you might prefer) it doesn't matter if one positions the centremark over the other end of the W/V vector .. ie the intersection of the TR/GS and W/V vectors. This is what happens if the W/V vector is drawn "wind up" from the centre point .. actually it makes more sense to think of the W/V in this case as being plotted down from the end point to the centrepoint of the rose as the direction of the wind as plotted is exactly the same.

The instrument plots exactly the same triangle regardless of which approach is adopted. To see this more easily, try drawing an example on paper and then orient the paper with the instrument. To change from one technique to the other is just a matter of moving the instrument "over" the triangle to reposition the centrepoint while, at the same time, rotating it to remain aligned with the radial spokes of the grid.

The solution is read exactly the same for each case .. it doesn't matter which technique is used .. provided no careless mistakes are made, the correct answer results.

The suggestion that the unconventional technique can save a little effort is true, but rather illusory.

It may be helpful to look at the typical navigation problems which we routinely solve on the instrument.

(a) Given W/V, TR, and TAS .. find HDG and GS

The conventional "wind down" plot requires some iteration on the part of the pilot to obtain the solution. The alternative "wind up" technique gives the answer directly. Just be careful of confusing the decal markings.

(b) Given TR/GS and HDG/TAS .. find W/V

Either way works fine.

(c) Given HDG/TAS and W/V .. find TR/GS

The standard way works fine. If you use the "wind up" method, you end up having to do the same sort of iterative processing which the technique sought to avoid in (a).

(d) Given W/V and TR/GS .. find HDG/TAS

Similar to (a).

I really can't see that there is any significant advantage to be had in using the alternative method. If you take the small workload reduction in (a) and (d), you end up with the same sort of problem in (c). A matter of preference, I guess.

. .CR

The CR works a little differently .. to save size .. which offers the advantage of its being able to be carried in one's shirt pocket.

To remove the need for a bulky slide, rather than plotting the standard triangle, a line is drawn through the intersection of the HDG/TAS and W/V vectors and perpendicular to the TR/GS vector (or its extension). This results in a triangle to be plotted which is solved by a combination of figuring simple vector components (left/right crosswind and head/tailwind) and doing some basic trigonometry using the sine and cosine scales around the outside of the instrument (drift and effective TAS) .. the result is no need for a slide with the radial/range grid. It is, however, quite important to remember that we are solving a different triangle from the Dalton, although the end result is the same. A lot of people tend to get confused by this difference.

Unlike the Dalton, there is no need to plot the W/V vector as such and the idea of "wind up" and "wind down" is rather unnecessary. However, the distinction can be made by plotting the reciprocal of the conventional vector .. ie as if the wind is coming from the reciprocal direction but with the same magnitude (speed). Alternatively, this vector can be thought of in the same way as the Dalton situation in that it is just plotted, for curious inconvenience, downstream at a scale distance equal to the wind speed.

The result is that the unconventional plot ("wind down") causes the conventional CR triangle to be rotated 180 degrees about the intersection of the TR/GS and W/V vectors (the rose centre point regardless of which approach is adopted). The pilot must keep this firmly in mind .. while the resolved components of the W/V have the same magnitude the sense or direction, with respect to the instrument markings, is reversed. Provided that the pilot does not make any careless mistakes, the answers are going to end up the same regardless of which technique is adopted.

The standard problems listed above for the Dalton work fine for the CR, regardless of which technique is used. However, with the unconventional method, the mental housekeeping workload on the pilot increases significantly as does the likelihood of careless errors. For the life of me, I can see absolutely no advantage to be had in using the CR instrument in other than the conventional manner. If you want to do so, fine ... just be a little bit careful of the housekeeping workload .. but, surely, it is a bit like marching around the parade ground backwards ? .. a novelty but of little practical value.

. .So, the upshot is that the wind up and wind down approaches, for both computers, can be made to work fine for the typical problems we have to solve. I just can't see much point in using the unconventional technique for either instument, especially in the case of the CR.

. .Hopefully I haven't further confused the issues ....

Amazing, isn't it ? ... near 40 years in the industry and I had never heard of this "wind up"/"wind down" thing before reading this thread ....

[FRIDAY]

I got the CRP5/W awhile ago and only recently have been try to familarise myself with it. The (W) i.e the wind arm on the windscale initially seemed to get in the way and annoy me and still does abit. When your beginning to learn this I presume it is best to be able to mark in wind point however I am slowly but surely just using the wind arm, not sure if I am using it right though. I was looking in the manual and what i gathered was you use the L end of arm on the H plate and vice versa H end on L plate, however when working on problems the L end on L plate seems to get right ans??? Also To those who use it,once you mastered it was the windarm a godsent or nuisance.

[Father Mulcahy]

The main benefit is speed. Once you've got it clear in your head, it seems to be a quicker method. Saves getting a felt tip pen out and then wiping off the disc. That's about it.

The main disadvantage is that if you get yourself confused, the whole thing goes out the window. I had to practice and practice to get both accuracy and solution right in my mind. Saw someone tear off the bar and revert to the pen 'cause it was causing him a nightmare on one question.

If you're having problems try this, the only advice I can give:

The L side of the arm goes against the wind heading on the H side and you read off the outer arm. You're reading off the high speed arm on the high speed side, just aligning the low speed arm against the wind heading. Vice versa for low speed.

It's easier to show someone than try and explain in text, and I apologise if you are totally confused now !

I did manage to pass G Nav and Flight Planning with a wind bar CRP-5, given the choice I wouldn't bother getting one again.

:eek:

FM

[Jinkster]

Does anyone own a copy of the Pooleys CRP5 CDrom just wondered what it was like before I decide to invest in it.

cheers

Jinkster

[razzele]

i dont have one ... but we have used it in class.

the content seems as you would expect.

unless u really are struggling and have money to burn i would stick with the green instruction book that comes with the crap5, i think that and working rough answers out will get you through.

[willby]

A note of caution to those using the CRP5 for Density Altitude questions in the General Nav exam. After failing the above exam by one mark in the Nov. Exams I was looking at feedback questions with my son. Using the CRP5 for desity altitude problems as suggested , it was impossible to come up with an answer that conclusivly indicated one of the 4 multiple choice answers. The CRP5 just was'nt accurate enough.
My son is registered with BGS and uses their notes and there was no mention of an alternative formula in place of the CRP5.
By chance we were looking through the Pooley's flight nav manual and after getting to the bottom of the section showing how to use the CRP5 for density alt. calculations we were amazed to see underlined in bold type
Until Further Notice Do Not Use The CRP5 For Density Calculations
In the JAR ATPL Examinations. Instead Use the Following Formula:

Density Altitude= Press. Alt. + ( ISA Temp. Dev. x 120 ).
Ater trying the formula on a few feedback questions glad to report that it worked a treat and indicated the correct answer clearly. Hope this note will help a few maybe get those vital few marks. Good luck.

[Send Clowns]

Sorry to hear someone might have failed on this point that is, in my opinion, a very silly, trivial JAA point.

I am surprised it is not in the BGS notes, which are generally very good, but your son should have been told in the groundschool segment never to use the CRP-5 for density-altitude calculations, unless it was a rushed last-minute guess narrowed down to a couple of answers. This is official advice from the CAA (and from me to any of my Nav students who read this, and I told the same thing to last week! My notes are very clear on this, and I don't think they even go into depth of how to use the CRP-5 for this, although the formula comes in that chapter). The answers are not precise enough from the CRP-5, and as far as I can see a different approximation is used by whoever set the scales, because some answers are quite different.

The correct way to answer these questions is, as you say, by using the formula (in the form others may find more familiar)

Density Altitude = Pressure Altitude + 120 × T

or the more accurate DA = PA + 118.8 T (our instrument lecturer teaches this, I don't know if the extra precision is required there. For Nav either is fine)

where T is temperature deviation from ISA, i.e.

T = OAT - (ISA temperature for that Pressure Altitude)

[onehunga]

I don't suppose there are any excel gods out there that have managed to duplicate the wind side of the CRP5/E6B and cracked the formulas for doing the various permutations that can be made. Perhaps someone has already produced what I am about to explain and willing to share?

Basically I face a very tedious train ride each week (3 hours each way) and so thought why not use this time to hone my skills on the flight computer before my ATPL ground exams. I could setup say 50 or so practice questions in excel. The spreadsheet would have an input area that would randomise the numbers that go into the questions and it of course would need to be able to produce an answer sheet as well. To simplify the spreadsheet I guess the questions would need to be in the same order etc but that is no bother.

The overall aim would be to hit a macro button or refresh the random numbers in the questions, walk to the printer in the office and grab my sheets of questions and answers and then off on the train to practice!

Any takers/ideas/criticisms (well hopefully none of those)??

[mazzy1026]

As an information analyst/developer I would be able to help you with the excel but I would think that you would be better using MS access and creating a database because it has much more functionality and you could have a table with all of your questions in and design some nice reports to print them out. This could probably be done in excel but would take 10 times longer.

Unfortunately I havent started studying the flight computer yet (pre PPL) but wouldnt have a problem in helping you design something if someone could provide the data you need.

Regards

Maz

[razzele]

i didnt really read ur post but i believe that OAT have a CRP5 instructuoinal CDROM available for sale.

good luck at staying completely sane in the next few months

[Send Clowns]

I have the basic formula for one of the functions of the CRP-5 on excel, if you need. The maths is not simple, but not too involved either. I seem to remember it is heading and groundspeed from TAS/trk/wind, but have not used it in a while - I used it for similar purpose to help me write quesions for the class. If you're interested drop me a PM with email address and I can send it on.

Send Clowns
General Nav Instructor
BCFT

[onehunga]

Thanks for the offers folks.

SC - pm is on its way.

Raz - thanks for that.

Think what I will do is to crib together what I have got in my mind probably in excel since I am crap on access and then open it up for (hopefully) construtive criticism. That way Mazzy if your offer still stands you will be able to at least see what I was attempting to do and then if needed cut, paste, reinvent or whatever into a more user friendly format.

We could well be onto something here that hopefully we can all share in and pass on.

Cheers again for the offers of help.

[mazzy1026]

Sounds great onehunga - show me anything you have made and it's no problem for me to knock something up !

Cheers

Maz

[Send Clowns]

Onehunga - I'll email it on Tuesday, unless I go into the office before then. How good is your maths, especially trigonometry?

[onehunga]

Abysmal but willing to learn :)

I am starting to think I might have bitten off more than I can chew. But hey always up for a challenge!

[flyingdogguitar]

Hi,
Just trying to get to grips with the old CRP 5 again!
Does anyone have a siple explanation how to work out Square roots with it??


Cheers

Dave

[M80]

Not having my CRP on me...

First up, get a rough estimate of the number you're expecting before touching the damn thing.

i.e. square route of 16. We're going to take a risk with 4 as our rough guess...


On the outer scale you'll need to locate the original number (16) and your rough guestimate, 4 (using 40 as the inner unit index is a 10... 40/10 = 4))

Put the inner unit index (the 10 in a black circle) on your rough estimate, 4, on the outer scale.

The original number, 16, should be opposite 4 (40 again) on the inner scale.


Obviously an easy example. For more complex numbers, home in with the rough guestimate and then slide the inner cirlce until the number opposite the inner unit index equals the number opposite the original number on the outer scale.

i.e. square route of 18.

guestimate 4

put the inner unit index on 4 (40 on the scale)

find 16 on the outer scale and you'll see that your guestimate on the inner scale is just past it.

Slide the inner scale back a touch until the number under the 16 is equal to the number opposite the inner unit marker.




Sorry for the lousy explanation! I find this method fastest in exams. Obviously spending a few nights messing around gets things a lot smoother...

I'll let someone else give you a better explanation now! :O

[flyingdogguitar]

Hi M80,
" Bye jove, I think I've got it!"





Cheers

Dave

[heinzmanm]

I'm sorry that I can't answer your question regarding alternatives to the CRP-5 but I can say that it is highly unlikely that you will find one in the USA. Unless you have someone coming to visit you over there who could bring one out for you, I'm afraid you'll probably have to pay the shipping from the UK.
As for re-selling on EBay, I've seen them on there for over £50. They actually have pretty good resale value as if you need one for studies, paying anything less than £72 for a new one is a bonus!

Matthew

[Tinstaafl]

The CAA will accept any slide rule type of flight computer, even ones that don't do high speed/mach No. computations. Of course you would then have to use temp. ratio tables but that's allowed.

You can use a Jepp CR type if you wish. That's what I & a number of others have used with very good success. We were all converting our non-UK licences to the UK flavour. The only catch is that UK instuctors are ignorant about them so entertain the notion that only CRPs are acceptable. No worries if you already know how to use one - or can learn from the instruction book.

[Send Clowns]

Use a CRP-5. The price is equivalent to 15 minutes flying on an MEIR course, to make your exams somewhat easier and less stressful! On the other hand if you buy on e-bay or from someone in the school who has finished exams and doesn't need it for the flying, and then resell it afterwards, it can be very little cost at all.

The CRP-5 has 2 advantages: it is one of the 2 best-made flight computers I have come across, and I have had many including an alluminium E6B, and most importantly the exam answers are found on it by the examiners! There are slight differneces between the calibration of different instruments, so this is a real advantage in the exam. I believe that the new ARC-2 from AFE is more accurate (and cheaper, also the other of the 2 best-made) but that is irrelevant; you don't want the right answer, you want the answer the examiner got!

Send Clowns
Nav instructor
BCFT

[WX Man]

The best made flight computer I've ever come across is an electronic Jeppesen one.

Why can't the CAA get their heads out of their a*ses and move into the 20th Century? And when they've done that, they can think about moving onto the 21st Century.

Try NAC or EFT in Florida. They sell CRP 5s. Or look on ebay for a second hand one.

[Send Clowns]

Wx Man

They are genuinely not as good. Used correctly, as I taught you, the CRP-5 is quicker and you are less likely to make a silly error. Visual representation prevents much of the finger trouble that gets the wrong answer on an electronic calculator.

I took on a student who had failed Gen Nav twice - having taken his electronic calculator in without the invigilators noticing. He had US and Canadian licences, and was converting without bothering to do the whole course so didn't know how to use the CRP-5. I showed him how, covered a few other bits of the syllabus, he took the CRP-5 in instead and passed.

Anyway, your point is lost on the thread as TS has to address reality, where he cannot use an electronic computer legitimately.

[WX Man]

I know, I know, I know... it just annoys me that in this day and age Our Friends In Aviation House take such a dim view of electronic ones.

(I have to admit that I can do a TAS/GS/WCA problem quicker using a CRP 5 than with a Jepp FlightStar. However the formula you gave me for Excel in the spreadsheet I made is the quickest way for me to produce Nav Logs)

[Send Clowns]

Our friends at the Campaign Against Aviation, eh Wx Man?

[porridge]

Or one could purchase the top of the range flight computer the Aristo Aviat 617.
Bit pricey, but a superb piece of engineering and very accurate.

[WX Man]

The "poison dwarf" strikes again!!!

[A320sRcool]

How do I find KG per NGM
from fuel flow per kg/hr SG and fuel flow per hr , TAS, etc
It is a ATPL Gnav exam question table using CRP5
Having to fill out the blanks. There are more figures available on the table but I m assunimg the above is enough - as there is no distance I m a little confused in this question

[MikeAlphaBravo]

To obtain Kg/Nm, first work out your groundspeed as per usual using the CRP. Then divide Kg/hr by groundspeed.
Hope it helps,
MAB

[aerobatic sean]

Preparing for CPL ground school. Reading some good posts here recently on ATPL study and suggested prep by folks who have been there done that thing.
Points made included getting up to speed with the CRP5 wizz wheel and the importance of using the " wind down " method for all tr/hdg/wind calculations.
Why is this the best method as oposed to "wind up" - which I got taught?
I know the "wind down" method is stressed in several books - but I have never known why?
I will get on and relearn this new way!
Why the need to use only the Pooleys CRP5 wizz wheel - it is a lovely clear layout I agree - but I compared it side by side to my alloy American ASA B2 and my Aviat 617 - and could not see any reason why all 3 wizz wheels would not suffice.
Sounds like I am out to buck the system! I am certainly not and it would be foolish to ignore the experience of other students who have been before and indeed the advice of instructors.
I know its been covered recently - but any other suggestions of pre course prep welcomed. Like others I am worried about the demands of Maths and Physics and will get the Keynotes booklet, the OAT Maths/Physics cd roms ( PC only - bugger - OAT promised 2 years ago they would produce all their CD roms for mac computers )
London Met College also produce a pre ATPL course maths/ physics revision booklet. Any other books suggested ?
many thanks

[EGBKFLYER]

Can't remember exact details but the 'wind up' method has some limitations and will produce errors for some calcs you have to do for CPL. As stated, sooner you get to grips with wind down the better. You were taught wind up for PPL because you generally have a known wind and only need to calc drift and groundspeed - wind up is fine for this.

There is no reason why you can't use any wizz wheel to do the exam with, so long as you can do all the calcs required. However, the man who wrote the exams used a CRP5 and therefore the answers you get will be closest to the exam answers if you use one too. Not that the other computers aren't right - but this an exam, not an exercise in producing the right answer...

[Megaton]

WInd blows rather than sucks so wind down is a much more intuitive method allowing you to gross error check your answers. If you have a search you'll find that there are limitations with the wind up method. INcidentally, haven't used either method since the CPL GFT!

[BIG MISTER]

All the books that I have ever read on the delights of the whizz wheel have always used the wind down method. So apart from anything else you'll get confused if you try and work through an explination.

I would also suggest that the exam questions are written using the wind down method. Sometimes the answers are a bit tight and its amazing how much time you can waste double checking an answer. So do yourself a favour and give yourself the best chance by using the same method yourself.

My last pointer is bin the pencil and get a good quality water based marker pen with a very fine tip. Makes your mark very clear to read and speeds up the process.

Good luck with the exams ! :}

[november.sierra]

I've successfully used the wind up method for my ATPL exams, and despite various claims that the answers obtained this way would be inaccurate, I must have got the correct answers since I passed both flight planning and gen nav with decent scores, so use whatever you're comfortable with.

I wasn't comfortable with wind down and couldn't visualise things, so stuck to wind up and it worked out fine.

[Blueskyrich]

Got Gen. Nav. this week and its just become very apparent to me - the CRP-5 isn't the most exact of instruments is it?

For instance, I'm going through the Bristol feedback questions. There is a question (Q317 for reference) where the the GS is needed for headings 090 and 270T. The W/V is 045/50 and the TAS is 180.

Now, using my Pooleys CRP-5 for this, I'm getting a GS of 149kt for the 090 heading, and a GS of 218kt for the 270 heading. However, after getting the question wrong (as the calculated GS were wrong), the feedback says that the GS should be 141kt and 212kt respectively. Its a fair difference and because of the answers available (two very similar answers), I was wrong.

What is everyone's take on this? Also, if anyone could check the answers for me, I'd be dead grateful :E

BSR :ok:

PS. Thanks to the Mod who popped this on the end of the CRP-5 thread - didn't even think to search for a previous and relative thread. Consider my wrist slapped ;)

[AndrewOO]

Good day,

Can some-one kindly tell me the difference between an E6-B & CRP-5, in a few words. I am allowed to use either?

Andrew.

[bobster1]

You can use what you want..but the atpl exam answers have been calculated using the CRP-5, so we have been told, there is slight differences in calcs using other manufactures flight computers..good luck!!

[AndrewOO]

Thank you.

I am sure that aviation examiners know that there are slight variations in aviation physical constants throughout the world, and aviation being an international issue would take this into consideration. I am also sure that the examiners are aware that different types of aviation computers are available, and take this into consideration in their answers, when it comes to a written paper. On a multiple choice question/answer the correct answer can be derived from rounding numbers. What I was looking for is if there is a difference in the physical quantities calculated by the E6-B, and CRP-5, that would retard my answer, and choose the best accordingly. If they both calculate the same things, I will get an E6-B.

Andrew.

[EchoMike]

E-6B doesn't do specific gravity, it assumes gasoline weighs 6 lbs per US gallon. CRP-5 does, you can use local value, but it is usually .726 or so for avgas, Jet-A is about .8. The CRP-5 will also give you fuel weight in kg in one calculation.

Ergo, CRP-5 can be used for any airplane, anywhere, E-6B is best for piston engine airplanes in USA, but still usable anywhere else.

Accuracy is about the same - the larger CRP-5 makes it slightly easier to read, but remember the real-world figures you base your calculations on may not be totally accurate to start - the 8 GPH might actually be 7.9 or 8.1, the 20kt wind could easily be 15 to 25, and so on.

E-6Bs are much less expensive, as cheap as $12.00, made of the finest grade of aviation rated cardboard - aluminum ones are about $30, and with most of the E-6Bs, the *instructions are printed right on them!!!!* which is a brilliant idea!

The "instruction booklets" are awful and will make you want to take up surfing instead of aviation . . .

I teach this stuff in ground school - a little practice makes it easy.

Best Regards,

Echo Mike

[AndrewOO]

Thanks Mike.

I will get both, now I hope a PA-28, C-172, C-152 is the same in Nairobi, as Prague, London, Miami, Tokyo, or Sydney.

Andrew.

[Tinstaafl]

I just can't work out why the UK is so anti-'CR's'. People in the UK just ignore them yet they're at least as accurate (even more so, in my experience) compared to the CRPs that are so popular in the UK. Some problems even require fewer steps to calculate using a Jepp. or ASA CR computer compared to the CRP.

[AndrewOO]

I guess with the E6-B, CRP-5, and a navigation plotter most if not all Flight planning, and navigation general aviation tasks can be done, which in an airline scenario is done by professional flight planning software, addition of the CRs would probably complicate tasks to be done by a GA pilot. I have finally decided to settle for one of the FAA approved electronic E6-Bs, and a UK CRP-5, together with some sort of professional flight planning software, with an international database.

Thank you.

Andrew.

[BlueRobin]

The critical difference iirc is the lack of a Mach No Index.

If you are looking to save a few bob for JAA ATPL by gettgin an E6B, don't. You need the CRP-5, or equivalent spec.

[AndrewOO]

What I actually want is to be able to seal, and open a flight safely. So my concerns are my abilities to do that with the right tools, but that is another topic. In conclusion I will get an Electronic E6-B to be used to cross check my manual calculations with the CPR-5, and other navigation calculations. I believe the German Aviation authorities allow the Electronic E6-B for their JAA exams. Like wise I expect to get Professional Flight planing software that covers my region of aviation activity to cross reference the manual flight data.

Thank you all.

Andrew.

[frodegh]

Hi!

The CRP manual tells you to use wind UP for questions on heading and wind DOWN for questions on track. So far that has worked 100% for me, with questions from bristol/atponline.gs. It makes sense as well, if the CAA use CRP as reference.

Blueskyrich's problem doesn't match though. Using wind-up gives the correct speeds, but considering the question gives headings, and not tracks, wind-down should be used according to CRP manual.

I'll definately be going with UP for headings and DOWN for tracks on my exam next week, but will try both if I don't get a good match (unless the alternatives give it away).

Anyway, here's a quick walkthrough of the two methods
Find heading/gs: Mark wind upwards, set track, set TAS on wind mark, read GS in center, read WCA.
Find track/gs: Mark wind downwards, set heading, set TAS in center, read GS at wind mark, read drift angle.

And by the way, either method gives the same results on both E6B and CRP models. You just need to look away from the detailed wind-up description on a E6B when doing questions on track.

I would never do the exams with an E6B though, as it lacks the high speed side, the mach conversions and more.

Edit: Just tried with some of the "Find w/v" questions on atponline.gs as well (where you have both hdg and track). Answers are a little off with wind up, and match perfectly with wind down.

[Jaguar Pilot]

Does anyone here know that the"CRP" in CRP5 or CRP1 stands for "Computer Robert Pooley"?

It is an entrepreneurial and commercial adaptation of the original RAF Dalton navigation computer (the aluminium one which does not warp in sunshine). Both are simply analogue slide rulers.

May I assure you that the questions in the JAA question bank allow for production errors/tolerances in all navigation computers so that, providing you use correct techniques, there is no way that you can derive an incorrect answer.

Since this is my profession, I just thought I would mention it.......

...and long live the Flight Management Computer! This is free of charge and comes ready-installed in your jet.

[paco]

The E-6B was developed in the United States by Naval Lt. Philip Dalton in the late 1930s. The name comes from its original part number for the US Army Air Corps in World War II.

I took to the Jeppesen one as soon as I saw it and have not used anything else since, including on my exams, although the small one is kinda hard to read at night. I can also recommend the AFE product as a better precision instrument than the CRP-5

Phil

[HappyFran]

I'm at the beginning of ATPL, been told I need a CRP 5
Clever it may be, but £75.00 WHOWW:eek::eek:

What happens to the old CRP 5 when all you fATPL's get snapped up and whisked away to play on shiny new jets with built in calculators ???

Does anyone have a much loved but used one they are willing to re-house (for a reasonable consideration) to a somewhat impoverished, but loving home ??:bored:

[AndrewOO]

Actually on most flight lines flight planning is done for flight crew by administration flight ground crew. There are specialized flight planning organizations, and software that can do this for you, as well. This simply increases pilot comfort and safety, by the reducing the burden on a pilot. But if you fly a Charter, Corporate, Private(Yes some Private Pilots have ATPLSs) aircraft you will find that you have to do the flight planning yourself much of the time, and a CRP5, E6B will be a very useful tool. Navigation, and flight planning are syllabus requirements every-where as they help you understand, and compute flight issues, and solutions, so a CRP5, or E6B are a requirement. Without a CRP5 or E6B you will be reduced to using a slide-rule, paper and pencil, and I assure you will be frustrated, and make endless mistakes. When you get to your ATPL jet may find you still enjoy spending an hour or two at home before an international flight doing flight planing calculations to cross check with your flight line ground crew. When you will have finished, you would probably throw your own calculations, and CRP5(E6B) into your flight bag, and head for the airport for the flight.:mad:

[Eavr]

If someone is looking for a course on how to use a CRP5 flight computer I found this course very useful. It is called "How To Use the CRP-5 Flight Computer and Smash the Exams" and is free. Hope that helps.
https://www.udemy.com/crp5course/