Scottish D&D Question
 

No doubt some of you will be watching the other thread on the use of 121.5MHz. As an airline pilot who still does a lot of light aircraft flying as an instructor and an examiner - I can't praise the D&D controllers enough and the facility for practicing is a fantastic tool.

Anyway I was on my own today in a bugsmasher whilst ferrying it down for maintenance. Whilst en-route I decided to do a practice pan with Scottish D&D. I wanted to get as much out of the exercise as possible so I ensured that I was well below coverage for auto DF fixing and switched the transponder off. The D&D controller ended up liaising with the Coastguard in attempting to fix my position.

The end result was a bearing from an airfield with an 'approximate distance' which was reasonably accurate. Just wondering how the Coastguard and D&D arrived at that position. I presume it was using DF fixes but I would be grateful if someone could clarify what would have gone on. I believe the position is manually plotted? Any information gleaned would be useful for passing on to my PPL students.

Thanks again to the chap on the other end of the radio. I think he valued the practice just as much as I did!

At Scottish D&D it is done by 3 staff telephoning 3 differrent coastguard stations (or some airfields), asking them to switch the DF equipement from "marine VHF" to "Air", then getting you to transmit whilst they get a bearing. You may have been asked to wait for a few moments whilst the calls were made, and then make a long transmission - normally a count to 5.

These 3 bearings are then manually entered in to a PC program which plots your location on a map and displays the "area of uncertanty" triangle. The program will also give a range and bearing from your approximate position to one of many listed sites.

The plotting can obviously done manually as well.

London D&D have Auto-plotting.

Simple really.

Hey Geezer,

Glad you made it in one piece. :}

So what part of bandit country were you ferrying to? Still working hard I see. ;)

MC

I was going to Perth at the time.

Working hard:} Think I have entered semi retirement!!!