Todays earworm comes from a hybrid of Blondie and my most recent lesson. If you’re unfamiliar with the expression “earworm”, it’s the annoying phenomena where you have a song, tune or even spoken phrase stuck in your head… “so One way, or another, I’m gonna divert, I’m gonna divert, divert, divert, divert, diiiveeeeerrrrt” is the ditty that has been spinning round in my head faster than a 45 degree turn.
What is a diversion then? Its the action of going somewhere else while in the air to avoid something, such as a pocket of weather (especially flying under VFR), an airfield closure or to avoid a pending situation. Anything, essentially, that requires you to deviate from your planned route and re-calculate your journey in the air.
I thought I would find this element of my training daunting, overwhelming and really quite difficult but, with some careful pre-planning and some clever little additions to my FLOG (flight log) tools it was one of the most fun lessons I have had, in part I think because the practical aspect of flying is becoming more autonomous, the actual flying of the aircraft needs less conscious thought so to speak. I’m also making an effort to use the rudder controls more effectively leaving my hands free for other tasks – like charts.
First thing, is planning. Navigation (and therefore any diversion) is all about planning. It’s also as much about flight safety and competence as it is working out where you want to go and how to get there and much of your “diversion work” can be done on the ground. Once you have planned your route and entered it on your flog, you can do a couple more calculations to provide you with some in-flight information which is easily accessible if your maths is as poor as mine. You’ll see attached to this blog a “Ground Speed Chart” which you may download, laminate and use (right click and ‘save image as’). This proved invaluable to me. It takes the in-flight thought out of the “MAX DRIFT” calculation 60/TASxWV which for me might as well be calculating string theory. Remember, “Diversions” are all about educated, considered estimations. Your calculations don’t need to be accurate, just a close ‘guess’. I’ll show you how to use the tool and others in the attached video.
A REALLY useful tool to have with your chart at all times is the CPM 1 diversion ruler, which gives you distance and time based on ground speed (which you’ll work out using your GS-Chart). There are other rulers and tools available of course but I find the CPM 1 most effective. There are some clever pilots pens that have a the calculations printed upon them for example.
You’re on a planned track and, for one reason or another, you need to divert (“one way or another I’m gonna da da, da da da da” – there it goes again) First you pick a point from where you can divert, somewhere enroute that you can positively identify, perhaps even your next waypoint. Then circle the new destination, ‘the diversion’ and freehand draw your diversion track. Using a protractor, or to make life easier the handy cut-out-and-keep Groudspeed Chart figure out the bearing (an educated, guestimation is all you really need) and enter this on your log… using the ‘max drift’ figure you have already calculated you can adjust your HDGT (Heading True) to suit and then add the compass deviation required. Groundspeed you can work out based on the bearing and by referring to your pre-planned groundspeed calculations, as presented to you on your GS-Chart. Finally its over to the diversion ruler, or CPM 1, whichever you prefer, to work out the distance and how long it will take to get there. Don’t forget to update your ETA (estimated time of arrival).
Thats it, in a nutshell. Diversions are not as complicated or scary as you might think. They’re intense sure, but think of it more like orienteering, but airborne so its just way, WAY cooler.