How did YOU cope with the skills test diversion?

[bamboo]

Can anybody give me some tips on how to best handle the 'unexpected' diversion in the skills test?. .. .I'd personally prefer to use the whiz wheel to calculate the wind drift and true heading, but have been told that it is impracticable to use during the test, because there isn't time to get it out and use it.. .. .Consequently, I've been practising different mental techniques of working out the wind effect, (both from my instructor, and what I've found in articles/books), but find that I can use the wheel faster!. .. .What methods have other people employed, and how good did you find them. Any help appreciated, as skills test is looming on the horizon, and scaring the s*** out of me with this uncertainty

[Bluebeard]

Forget the whizz wheel, unless your are sh*t hot at using it you will be wasting your time. Concentrate instead on radio nav and handy rules of thumb.. .. .Don't forget you can use radio aids during the diversion, so be very clear as to how to use these and which ones you will use during the test. . .. .A rule of thumb I use for calculating drift is that the max drift you will encounter (ie if the wind if 90 degs. to track) is 2/3 of the wind at height transposed to degrees e.g. if the wind is 15kt then your max drift will be 10 deg. This is not 100% accurate, but it is likely to be more accurate than you can fly.. .. .Also, have you measured your thumb? Mine's 10NM from tip to knuckle, quite handy for shorter diversions. . .. .Finally, remember that the examiner is not looking for perfection, he is looking for safety and a reasonable degree of accuracy. During my test I almost screwed up my diversion as the actual wind was very different from forecast, during the debrief the examiner suggested that I could have routed via a nearby VOR and then used that to track straight to the diversion point.. .. .Good Luck!

[paulo]

I did a quick rule of thumb; found a straight edge, drew a quick line, measured up a rough bearing.. .. .In my case, once on course, I was uncertain of position for quite awhile, but decided that - in the absence of any currency on Radio Nav - I would stick to my planned heading. Going off for a look-see seemed like it would really confuse things.. .. .Examiner afterwards said I'd done the right thing (he sensed I was 'lost'). I got my target right on the nose.

[Wrong Stuff]

A refinement to Bluebeard's method is to work out the speed & heading corrections for 30, 45 and 60+ degrees when you're on the ground. Write them down on your flight planning sheet. Then when you've worked out your required track it's fairly easy to see roughly how much of a crosswind you've got and just apply those figures to the track and airspeed to get your heading and groundspeed.. .. .Don't forget to let the examiner hear you adding on the correction for variation, too.

[phd]

Bamboo. .the method Bluebeard suggests is the correct approach. However using 2/3 the windspeed to give your estimated maximum wind drift (the expected drift if the wind was perpendicular to heading) only works at a TAS of 90 knots. At 120 knots the max drift is 1/2 the windspeed and at 60 knots (if you fly a microlight for instance) the max drift equals the windspeed. This is all based on the 1-in-60 rule for calculating angles from vectors and you can read all about this in the very excellent Trevor Thom book 'Air Pilot's Manual - Air Navigation'.. .. .From the estimated max drift you can then use the 'clock code' rule of thumb to work out your actual drift and wind correction angle. The clock code says multiply the max drift by the angle between wind and heading divided by 60. If the wind is 15 degrees off your heading 15/60=1/4 so use 1/4 of the max drift as the wind correction angle, if the wind is 30 degrees off the heading 30/60=1/2 so use 1/2 the max drift and at 45 degrees use 3/4 the max drift. At angles of 60 degrees or more you assume the actual drift equals the max drift you have estimated previously. . .. .This method is simple and works. Combine this with using a simple angle plotter and drawing a diversion line on your map so you can estimate a track bearing and then apply the necessary correction to get the heading to steer and you should have no problems. The most important thing is to get onto the correct heading as soon as you reach your planned diversion point. Once you are going in the right direction, and can confirm this with ground features that agree with the chart, you should then have time to work out the distance to run, your ETA and still have enough brain left to do your freda checks.. .. .Hope this helps - it worked for me - got my licence last November.

[What a Loop]

I agree with Bluebeards method it is the one I used. I would add that finding an good reference point for starting the diversion is helpful.. .. .During my skill test the examiner asked me to divert whilst we were over the M4 at Membury, nice big mast there.. .. .Another tip was given by one of my instructors, I use the staedtler lumocolor pens and have marked onto it white rings at 10nm intervals, as a quick guide it worked well during a diversion. .. .Best advice is to relax and enjoy it <img border="0" title="" alt="[Wink]" src="wink.gif" />. . . . <small>[ 12 March 2002, 15:46: Message edited by: What a Loop ]</small>

[Spacer]

I found that by just picking a nice big feature, drawing a quick line on the map and adding drift lines, that you can quite qucikly guestimate how far out you might be, and then correct it. Just remember, always fly the aircraft first and don't rush anything. Don't spend too much time heads down.

[Aussie Andy]

I was shown a really simple shortcut for readily working out drift and GS without the need for any mental gymnastics:. .. .In a corner of your PLOG, draw a small diagram consisting of the 4 lines that cross over each other - one vertical, one horizontal, and two diagonal - to represent the cardinal points of the compass, and the ones in between, ie. N, NE, E, SE, S, SW, W, NW. [Simpler than it sounds - I wish I could add a diagram here!]. .. .Now, before you depart, work out drift and GS on your whiz-wheel for each of these points, and write this near each of the points of the diagram as appropriate. E.g. you might write "+9deg / 85kts" above North, and South (might) be say "-8 deg / 105 kts", etc. This only takes about 2 minutes to do.. .. .Having done this, when you come to doing a diversion, you just need to work out the TRACK (pencil, eyeball whatever) in the usual way, then just look down to the PLOG to see that drift you need to add or subtract for the direction concerned, and the GS to use for your EET calculations.. .. .If this doesn't make sense, mayeb I can clarify by email with a diagram.. .. .I don't use this every time I fly - but it sure helped me get through the skills test diversion last year - it went really well!. .. .Hope this helps,. .. .Andy

[TangoZulu]

There are a number of useful things which I have been taught which helped me with the skills test diversion. .. .a) Make sure you know your starting point - this may seem obvious but if you start from a vague "about here" it's not going to help - even if your start point is a few miles ahead on your planned track this should be no problem - a large town or suitable landmark - mine used Glastonbury Tor.. .. .b) A radio plotter is a great investment for only a few pounds - it fits in the shirt pocket, is marked in scales of 1:500 and also has the compass rose on it for plotting bearings etc on your map. It is also a good idea to mark the scale for say 2 minute segments at 90kts eg. 3NM so that when you draw your line on the mpa, you can easily estimate an ETA. .. .c) On the map, before I go anywhere, I draw a wind vector in a large, prominent place - the forecast 2000ft wind is good, along with the Max Drift - then apply drift as stated above 15deg = 1/4, 30deg = 1/2 and so on.. .. .d) Above all relax and the remember to Aviate, Navigate and Communicate (in that order !). .. .Rgds. .. .TZ

[suction]

I have a vague memory (in general) of something called a 'Knightson' Computer - which is a piece of circular plastic on which you can mark the wind vector before you go. Once you've marked your chart with your diversion you can slap the plastic on top of the line and it will show you the drift component in one easy step. I tried a search on the net but nothing showed up - I'll keep looking, but maybe I might be confusing it with something else.. .. .Suction

[Who has control?]

I too was shown Aussie Andy's method & I works fine. No mental arithmetic to get wrong, no fiddling with whizz-wheels. Just work out the track and apply the drift correction. It won't be absolutely spot on to the nth degree, but it will be near enough

[eyeinthesky]

Remember you can also use what's left of the drift calculation to work out the head and tailwind component to give you a G/S.. .. .Example:. .. .Wind 240/30 kts. Max drift for 90 kts TAS = 20 degs. . .. .Assume your diversion track means you calculate that you will use the clock code to assume a factor of 0.6 for the drift. This leaves you with 0.4, which you then apply to the number of KNOTS (not degrees) of the windspeed to give you a tailwind or headwind component (you should be able to work out which!). In the above example that component will be 30 x 0.4 which is 12 kts in round numbers. Your G/S will therefore 102 or 78 kts.. .. .To work out EET to the new destination, I find it is easiest to divide the G/S by the distance. Say you have a G/S as above of 102 kts and the distance is 50nm. 50 goes into 102 just over twice, so it will take you just under half an hour to travel the distance. If the distance were 24 miles then the same G/S would give an EET of approx 14 mins. It's close enough for PPL estimation and a lot easier than fiddling about with whizz wheels while trying to maintain height and heading and keep a lookout.

[BEagle]

When you are given the diversion, you should be told "When you are ready, take me to....". This will normally be given to you by the Examiner when there is a hugely obvious feature from which to set off clearly nearby. Lots of easy ways to measure angles, but I had checklists produced with a laminated back on which there was a 1:500 000 scale on one edge and lots of blank area on which to write. Use a chinagraph pencil, pop the checklist from where you're going to divert from to the diversion point on the map, draw the track line - measure the distance and scribble it on the blank area. Now wiggle the checklist across to the nearest convenient VOR rose and measure the track by using the checklist as a parallel rule. You now have track and distance - now apply Mental Dead Reckoning, jot down the heading and time, turn carefully onto the correct heading, check the DI and hack the watch. Update your estimate with map-to-ground work and there you have it!

[FlyingForFun]

I was shown the "wind star" technique which Ausie Andy described - works fine for me.. .. .As for distances, someone mentioned the 10NM thumb. You'll probably also find you havea 60NM hand, from tip of little finger to tip of thumb, if you spread your fingers - but as with the 10NM thumb, check this on the ground before you use it! One of my instructors has a very neat solution for measuring distances. She's cut the scale off the bottom of an old 1/2-million chart, and sellotaped it onto a pencil. She clips the pencil to her knee-board, and uses it for writing as she's flying along. If she needs to measure anything, she's already got a "ruler" calibrated for her chart - you don't need to carry anything extra for this method, which makes it quite neat.. .. .A couple of people have already said to start your diversion from a known place, which is good. (My examiner made me fix my position using VORs, then gave me a diversion straight afterwards - I already knew my position from the VOR fix, which was nice!) I don't know how the examiners feel about this, but in real life it's extremely helpful to fly to a prominent line-feature, e.g. a motorway, then follow the line-feature. Especially useful in weather diversions, when poor vis or low-level clouds will restrict your forward visibility making it difficult to spot individual points for navigation.. .. .But most of all, don't stress about it - go up with your instructor, try each of the techniques, forget about any you don't like - and enjoy it!. .. .FFF. .---------