My heart sank when the UK CAA has indicated that PPLs do not need to understand the 1 in 60 rule!
In that case can you enlighten us on its particular use in VFR navigation? It can be very useful in conjunction with instrument flying for calculating your lateral displacement but for VFR navigation, of which I have considerable experience of teaching, I cannot recal a single occasion when I have needed to use this rule!
The 1 in 60 rule is one of the things that annoyed me most about the IR exam. It is made for people without a clue about trigonometry and the IR exam had several questions where the correct solution using trig was considered to be wrong and you had to enter the wrong answer using this 1 in 60 crap. There were more cases where only the wrong answer got you the credit but the 1 in 60 was the most annoying of all.
One in sixty rule and drift lines are still taught. The PPL skill test still requires a ded reckoning leg with revised estimate (heading and ETA) at the half way point. Sensible airmanship would suggest getting out a wizz wheel while single pilot is not ideal.
Practically I just draw a line on the map, the relevant wind vector and my times. I use the clock code and max drift, which is close enough to basic trig, for WCA (sine) and cosine for ETA.
The article implied that there are several anachronisms still being taught. My thesis is that the one in sixty, clock code are basic trig concepts related to navigation and drift, which should be base knowledge.
I can’t recall the one in sixty for IR or ATPL/CPL, but it does come up for PPL. Trig tables would show the real answer is 0.96o at one in sixty, so surprised that exams force you to select the ‘wrong’ answer, as for small drift calculations it is pretty accurate.
I think one needs to see this against the background of the general collapse in UK school education. The good private schools are still good, but that’s only because they kick out the kids they don’t want and dump them in the State system (a procedure I am fairly familiar with). Also if you are paying £5000/term you tend to keep on top of what your kids are doing at school. There are also good State schools but almost only in the more affluent areas, where property prices are much higher as a result. The collapse of classroom discipline in the bulk of the education sector has made it possible to learn virtually nothing. Yesterday I saw an announcer on some BBC technology programme, aged c. 30, saying “would of” instead of “would have” (which suggests the only book she has ever read was facebook) but she is probably on £100k and could easily be doing a PPL somewhere.
The wind drift has to be taught somehow but it beats me how it should be done for the modern world. The average young person today will not have a hope in hell of getting through the PPL exams. One could say it doesn’t matter because most people doing a PPL are in their 40s plus so did do “something” at school, but it does prevent young people entering the system.
I think the slide rule
ought to be replaced because it looks like a joke even to somebody who does understand trig. But then how do you teach wind drift? OTOH, loads of experienced pilots actually believe that the aircraft is aware of the wind and if you believe that you will never understand the basic concept of wind drift.
Back to the original post – I think Skydemon are under pressure to incorporate every possible feature while they are out ahead and there is no real competition (in the UK, for sure). They have an Apple-like religious / cult momentum going in their various pilot forum threads which also prevents anybody saying anything negative about it without getting beaten about the head. When you have that sort of momentum you need to make the best of it – I certainly would if it was my business.
The challenge is how to incorporate the features without producing an unusable product. I have flown with a number of SD users and as far as I could tell most of them didn’t understant the features properly. A carb icing warning is going to be silly, on a product which sees only GPS data.
I can’t recall the one in sixty for IR or ATPL/CPL
There are quite a few “open” questions nowadays where you have to insert the answer. As each country can choose its own subset of the QB (question base), you might find many or none of them depending on where you are. The German CAA loves them, probably because most Germans associate multiple choice with “Who wants to be a millionaire” and not with real knowledge tests.
For the more involved questions such as doing a complete flight plan with multiple legs and wind correction, they expect you to use Spock’s wiz wheel which is a graphical solution and very hard to get a good reading. I refused to use it and just memorized the trig for WCA/GS (law of sines):
TAS / sin(WA) = WS / sin(WCA) = GS / sin(WA-WCA)
As there are multiple steps, the “error” accumulates. In the comment field for each question, I added that I have used the law of sines and outlined my rounding strategy, hinting that I will fight if they don’t credit me for choosing the correct solution over the 1850s slide rule approach. Well, they did give me full credit 
The funny thing is that my approach was actually many times faster and with less risk of making mistakes. And it actually forced me to understand what I was doing instead of operating this ridiculous slide rule in the way somebody taught me.
Getting back to the topic: I like SkyDemon. Great presentation and feature set. AirNav Pro is ugly and cluttered but SkyDemon isn’t.
Hmmm … a very sophisticated discussion.
I do a DCT and then check that Bearing and Track are identical :-) And most of the time I let George do it.
SD/AirNav:
I worked with the Developer of ANP for two years. When I started it had no real maps, no approach charts and it was even uglier than it is today. I did all the contracts with the DFS for the VFR and Approach Charts – and at the same time I tried to convince Mr. H. that the GRAPHICS should be really reduced to the max. From day 1 I hated the simulated Compass (!) that showed a GPS track (!) and stuff like that, but even after trying for 2 years I could not convince him to simply get rid of that stupid stuff. Of course such a collaboration will not survive, so i quit.
Today I’m convinced that vector based apps like SD will destroy ANP sooner or later. But I see problems with SD too. Of course the biggest one is the maps. This data has to be 100% correct and they better get that in order quickly (or i will unsubscribe :-)). And the graphics are (although much better than ANP) pretty old fashioned. Looks like from the 70s.
I think the slide rule ought to be replaced because it looks like a joke even to somebody who does understand trig.
It’s taken me a few months of head scratching, but I think I finally understand how to use the flight computer. I’m 31 and my day job is in digital. Using a paper slide rule feels so alien. Having said that, now I’ve learnt how to use it I have fallen in a weird kind of love with the thing. It’s simplicity is beautiful, but it does feel like it should be put to rest in the museum.
We’re taught to use the flight computer in pre-flight planning, not in the air. Too dangerous trying to fiddle around with it instead of flying the airplane.
In the PPL syllabus we learn the 1 in 60 rule, but have also been taught to use a simpler (less accurate, but accurate enough) method whilst in flight…
To correct track errors, I mark quarter-way, half-way, three-quarter way marks along each section of the route, with 10 degree fan lines. If I am off track, I use the fan lines and the distance along the track to calculate the correction angle using:
This will get you the total heading change necessary to reach the destination.
For en-route diversions, I’d use the max drift calculation with the clock code to calculate the approximate drift correction angle.
I refused to use it and just memorized the trig for WCA/GS (law of sines)
Reading that I remembered drawing little triangles when I took the written, and solving them from first principles. My memory is not that great 
Thanks for the memory.
The E6B was and is a neat device but its obviously not necessary to use it today. Mostly I follow the magenta line that magically appears on my primary chart, and that gives me a point on the horizon to point towards visually. Seems to work fine.
> How difficult is it to remember sin and cosine for 15, 30, 45 degrees?
Well it’d be a lot easier if we used radians rather than degrees (pi/12, pi/6, pi/4 radians) :-) Only joking (well, half. Everything I ever have done recently with trig uses radians rather than degrees).
However, for a typical VFR PPL is that even necessary? Ten years ago I navigated across the breadth of the United States using nothing but a combination of DR/looking out the window in a very slow plane whose ground track is therefore quite strongly affected by the wind. A method of estimation then successive approximations (reducing the wind correction by one half in whatever direction worked) very quickly resulted in a heading that would maintain the desired track over the ground. The winds aloft forecasts aren’t really accurate enough to make it worthwhile to actually use something as precise as the sine function. Sure knowing the background is what allows you to derive reasonable estimates – knowing the unit circle definition of the trig functions will make you grok exactly how the wind will push you around, but going to the bother of getting a precise output from a trig function for a dubious winds aloft function seems a bit over the top.
Personally I fly to get away from chittering devices (although I will use Skydemon, it’s awfully handy around complex airspace). This is why I fly an ancient aircraft full of WWII era gyros (well, that and I can’t afford a Cirrus).
> How difficult is it to remember sin and cosine for 15, 30, 45 degrees?
Well it’d be a lot easier if we used radians rather than degrees (pi/12, pi/6, pi/4 radians) :-) Only joking (well, half. Everything I ever have done recently with trig uses radians rather than degrees).
Well, if you understood the origins, you could picture the DG as a unit circle and calculate your sin and cos from there. Close enough for a rough inflight calculation.
Cheers,
