Suppose I'd better write this up whilst I am sober
I managed to bag an hour last Friday, which consisted of using the ADF (Automatic Direction Finder), NDB (Non Directional Beacon) the VOR (Very High Frequency - Omnidirectional Range) and the DME (Distance Measuring Equipment).
Firstly the the ADF. I read an article a few weeks ago, in which the guy who owns Cirrus, the aircraft company, absolutely slated the use of this instrument. Whilst I agree with his views on technology, and GPS, I can't see how you can criticise the ADF. It is a very useful, and simple to use piece of kit. Before I write further, remember this:
TITS
(Sorry - this one is for the lads!) It does have some meaning, when flying using radio navigation:
T - Tune
I - Identify
TS - Test
Here is a perfect example of how I will use the ADF. I am flying around to the south of the Liverpool zone, lets say I have just taken off from Sleap, and I wish to return to Liverpool using Oulton Park as the VRP to enter the zone. Those of you who have flow at Liverpool, will know that this can be a difficult area to find. So, I TUNE in the ADF to the NDB on the frequency 368.5 - I then enable the Nav radio in order for me to listen to the Morse code to IDENTIFY, which consists of a series of dots and dashes. Once I have established I am tuned into the correct station, I can then begin navigating to it. The needle on the ADF display will now point directly to the station (TEST) (giving SLANT range - 10 points to whoever can tell me what this is - very important for those taking Nav, I should know)
There are a couple of methods which come next, including holding your pen on over the needle, and transposing it's position over your heading indicator (an often frowned upon method). Make sure you synchronize your heading indicator/DI with the magnetic compass at this point - then, turn the compass card on the ADF to zero. Make a note of the number it points to (not a heading) and add it to the heading you are flying. For example, you are flying roughly north, lets say 010 degrees - having set the ADF to zero, the needle points to 090. Add 090 to 010 to give 100 degrees - this is the heading you fly - making sure you have synchronized the DI !!
I suggested to my instructor:
'Well why don't you just set the ADF card to the actual heading you are flying - then the needle will point to the heading you need'?
Apparently that is a more advanced technique - something which is learned in the CPL course. Anyway, as you get nearer to the station, the needle will start to flicker (if you manage to stay on track) - this means you are getting close, or perhaps over the station, by this time you know where you are (or should!).
VOR
The VOR is a brilliant piece of kit - one which is extremely useful. The use of this instrument is similar to the ADF, in that you tune to it, identify it, then test it, by rotating the OBS (Omnidirectional Bearing Selector - or the rotating compass card) through 360 degrees, checking that you see the needle deflect either side, and that you get a TO and FROM flag. You need to know if you are flying TO or FROM - if you are flying TO a station, then you rotate the OBS until you see the TO flag, then you keep rotating it until the needle is aligned, which means that the number at the top of the needle, is the heading you need to fly to take you directly to the station - you are flying the reciprocal of the radial. If you fly the RADIAL - then you are tracking away FROM the station, and to do this, you do exactly as above, except you have a FROM flag, indicating you are flying away from the station.
If you tune into two VOR stations, and obtain your heading from the station (QDR) then you can plot your position on the chart, with surprising accuracy. My first attempt at this was freehand, which was a big mess, not very accurate at all. The second time, I used my protractor, and discovered that we were above a grass strip, and I was made up having looked out the window to see that we had just flown over a grass strip!!
It was a very successful and enjoyable lesson, one which I will need to remember and practice for the GST.
Hope you all had a great Christmas, and look forward to seeing some of you at the fly-in.
Regards,
Lee
