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Welcome to the CPL Navigation question and answer forum. Please feel free to post your questions but more importantly also suggest answers for your forum colleagues. Bob himself or one of the other tutors will get to your question as soon as we can.
Just wanted to debrief all readers re my penultimate CPL exam, the CNAV - which I comfortably finished this morning and scored 76%.
To be honest, I was a tad bit dejected with 76% - this was certainly one exam (apart from CADA) where I went in guns blazing, thinking it would be an easy high-score but I guess CASA's surreptitious word-play coupled with some very silly mistakes on my part might have cost me some easy marks. But, a pass is a pass, and in the spirit of serving the BT Forum community, here are my key takeaways and tips:
- As always, Bob Tait's books are the way to go - There's also an additional workbook as part of the subscription package. Make sure you attempt the questions within the workbook as it will definitely give you an edge once you're confident with the more complex 1 in 60 questions,climb/descent/CTA step calculations and fuel planning - speaking of which;
- My question-bank consisted of 32 questions, consisting of 1 and 2 mark questions. The questions were a mix of nearly every topic from the book. Instead of the questions being skewed/weighted towards a large number of 1 in 60 questions, I had a near equal set of everything - from CAS/TAS calculations, xwind calculations, to CTA step navigation, circa 4 or 5 simple and complex 1 in 60 questions and basic and advanced fuel calculations. I was also asked two questions based on the PCA (identifying the Flightwatch frequency) and identifying which GAF to use from Swan Hill to Canberra). The other chart based questions were from the Sydney WAC (a complex 1 in 60 based on diverging tracks) and the Hobart VTC (identify a location where terrain is higher than CTA LL).
Also, pay close attention to the units of measurements as this is what can easily trap you into entering the correct answer but in the wrong units - thereby costing you valuable and easy marks. Oh and don't forget to be confident with BOD/EOD calculations - I was asked 4 questions on these!
- The 1 hour 45 min time limit is more than sufficient. I did one revision and thought it was good enough. But my recommendation is to do multiple revisions if time permits so you can iron out any careless errors and score a higher mark.
- CNAV is NOT hard per se, when you compare it with Performance or even Air Law (which can be a challenge due to the 80% pass mark and constrained time limit) but it is VERY easy to make silly mistakes. The key is to keep practising the quant questions and read the bits which involve a lot of theory (such as understanding Conical/Mercator projections, latitudes and longitudes and differences between geographic and magnetic poles etc). Personally, given that I had already completed CFPA and CALA before I attempted CNAV, it helped me sail through revision of things like Pressure Heights, Transition Levels and fuel planning. So my recommendation is to attempt CFPA-CALA-CNAV, in that order.
- Lastly, Bob Tait's text contains a chapter at the end that deals exclusively with Navaids. This is an excellent chapter to understand basic instrument flying and concepts around GPS - I actually found it a near identical copy of the first two chapters within the IREX book. A good read of this chapter sets you up neatly for the more chunkier parts of IREX. I was asked only one question re the VOR but as everyone gets different question banks it is like you could be asked questions surrounding T.E. and Drifts using ADF's.
Hope this helps - now onwards to the final one - CAGK!
moist_croissant replied the topic: Passed CNAV - 76%
I passed CNAV this morning 21 Feb with 91% after 8 days of self study with the BT Book. I read your post and just thought I'd add to it as my exam question bank was vastly different to yours.
I had the same amount of questions, 32 in total. 10 of them were 1 in 60's with another 10 on ROC & ROD (most of these are straight from the Day VFR workbook). Cancelling SARTIME on the gnd in Inverell NSW (HF Freq). GAF's needed from ACT to town in NW Vic. What cuts meridians at the same angle. A fuel calculation for a PVT Day VRF flight asking for minimum start up fuel for a 169min flight at a given fuel burn (It says not to include the Fixed reserve, so RTFQ). The two Purple dotted lines east of Brissy, What are they. 3 mins late at 60NM of a 90NM flight what time will you arrived a 90NM (No GS given). A simple gallon to litre conversion question.
I did not have any questions that I had to convert litres to gallons or kg/lbs with in the fuel calculation questions. That's not saying you won't, as you can see from this forum two exams in the same week had two vastly different question banks.
Good Luck to everyone sitting CNAV soon, Don't underestimate it or you will fail it very quickly.
Seems like we had some questions in common but you appear to have had the more prevailent question bank - consisting of a number of 1 in 60's. I was a bit taken aback when I noticed of all things I had 4 BOD/EOD questions ..it pays to revise these from the PPL era lol.
So true - can't take this exam or any of them for granted!
Congrats on the pass and good luck with the remaining ones!
When you try relate the CASA Nav exam to the requirements of the real world there seems to be a bit of inconsistency at times. CASA suggests that when you use a calculator to arrive at an answer, you should keep all of the decimal places and then round the final answer to the nearest whole.
When you try to workout a PNR in the real world a couple of problems arise.
Firstly, when you assess the amount of fuel you have in the first place, you poke a stick in the fuel tank and have a guess at how much fuel is in there. It's a bit hard to get that figure down to a ten thousandth of a litre.
Secondly, when you calculate a ground speed out and back you base it on a wind that comes from consulting a completely useless GPWT graph that's calibrated in pressure heights at the exact mid point of each grid and then make multiple interpolations across five or six grids and between pressure heights converted to altitudes.
Then you use the figures obtained to do calculations to multiple decimal points and pretend that the answer is super accurate.
"Secondly, when you calculate a ground speed out and back you base it on a wind that comes from consulting a completely useless GPWT graph that's calibrated in pressure heights at the exact mid point of each grid and then make multiple interpolations across five or six grids and between pressure heights converted to altitudes."