View Full Version : QDM procedure


Put1992
7th Apr 2008, 00:01
Could somebody run through a normal QDM procedure for me please?

Thanks

Put



FlyingGiant
7th Apr 2008, 02:46
"QDM QDM Exampleton Approach G-ABCD request QDM G-ABCD"

"G-ABCD Exampleton Approach QDM 050 Class B"

"QDM 050 Class B G-ABCD"

Notes:

1. The initial "QDM QDM" was a tip given to me by the chap who did my R/T exam, whose day job is as an ATCO. It gives the guy on the other end an early warning to flick the switch on the DF equipment that makes it read the reciprocal bearing you want rather than his bearing to you from the ground station, which it's more likely to be set to.

2. No need for initial call, pass your message & all that. Just pop onto the frequency, get the bearing, read it back, you're done.

3. Class B means 5 degrees accuracy & is probably the best you'll ever hear. Class C means 10 and Class D means he's pulled the number out of his a**!

lurker06
7th Apr 2008, 11:33
You may like to have a look at CAP413, the CAA Radiotelephony Manual, which has all you need to know (and more!) about RT procedures. You can download a free copy at http://tinyurl.com/3odufb

The QDM procedure, as explained by FlyingGiant, is on Page 10 of Chapter 6.

Regards

Lurker

chevvron
8th Apr 2008, 08:43
Exactly how I was taught on my PPL course. Trouble is nowadays, students tend to be taught to ask for QTE, which civil D/F equipment often can't show,( I think the RAF can do it though) so we just give QDM and variation.

Keygrip
8th Apr 2008, 13:14
Lol, that's a bit mean chevvron - they ask you for a true bearing FROM you, and you give them a magnetic bearing TO you and the variation? Not much mental arithmetic there then?

Seriously though, if your kit will show QDM surely it will show QDR, are you allowed to apply variation yourselves and then give the pilot a QTE that they asked for?

I would think if they actually needed to ask for a QTE then they are trying to plot position - which by default suggests that they don't know quite where they are (maybe completely lost) - so a touch of Disney magic would be welcomed (cast members going the extra mile for guest satisfaction).

I'ts a shame that VDF is now being written with the letters GPS.

FlyingGiant - should that call not be to Exampleton Homer, not Approach?

funfly
8th Apr 2008, 16:25
With my memory I can never remember if a QDM is a from or a to :confused:
Anyone got a little rhyme or something to tell me which QDM is?

Shunter
8th Apr 2008, 16:37
DM - direction magnetic
DR - direction reciprocal

Don't know any songs :(

coodem
8th Apr 2008, 16:39
QDM is magnetic bearing to steer to the station. Sorry don't know any rhymes to help out.

One other thing I have not seen mentioned, is to start your message with HOMER, this prepares the controller, that way he has a bit of time to set his system up.

Bravo73
8th Apr 2008, 18:18
Anyone got a little rhyme or something to tell me which QDM is?

QDM takes you back to 'Mother' (ie base). Works for me anyway... :O





One other thing I have not seen mentioned, is to start your message with HOMER, this prepares the controller, that way he has a bit of time to set his system up.

What's this got to do with the Simpsons, eh? ;) (Sorry couldn't resist.) :O 'HOMER' must be an FAAism. As mentioned above, in the UK, you generally prefix the call with a couple of 'QDM's to alert the controller.

Shunter
8th Apr 2008, 18:51
Homer was used in my RT practical. Barnsley Homer, if I remember correctly.

coodem
8th Apr 2008, 18:52
Just looked at the CAP, but could not find anything, Looked at my ATPL notes and found the actual question in the brushup papers.

Went like this
How should the direction finding station first be addressed?
Ans = HOMER

I did a JAR ATPL, so its got to be JAR. Has anyone else heard of this phase before?

Edit
Just noticed Shunter has heard it, phew, I thought I was starting to go mad

Robin400
8th Apr 2008, 19:29
INBOUND hear more steer More
OUTBOUND hear more steer LESS

spekesoftly
8th Apr 2008, 21:25
I suggest the term 'Homer' (in the UK if not elsewhere) is an anachronism dating back to the days when ATSUs had dedicated D/F operators. Nowadays requests for QDMs will normally be answered by the Approach Controller, who may not even recognise the term homer!