Intercepting QDM’S and QDR’S (fixed card ADF)

[3 green's]

Can you help?

Intercepting QDM’S and QDR’S (fixed card ADF)

What method do YOU use when doing the above?

Personally I use the “parallel method”, as it is just about fool proof (KISS methodology)

Thanks for the help

Cheers

Paul


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every flight is a training flight

[BIK_116.80]

First thing you must do is stop using stupid terms like QDM and QDR which were designed to confuse the enemy during WW2, and which have been confusing pilots on both sides to this day. As terms which were designed to confuse, they are now well and truly outdated and their use should be banned. They are quaint RAF terms which have seen their day.

Best of luck with th ADFing.

[Honest Frank]

BIK - what terms would you use then.Surely nothing can be as quick and easy to say (even if it does confuse the enemy)as QDM etc......

[BIK_116.80]

Radial.

[Tinstaafl]

Not correct to describe NDB bearings as 'radials'.

I prefer 'Bearing to Station' & 'Bearing from station' as appropriate. Every time I've asked someone what QDM then those terms are the succinct reply. Most Oz books use BTS & BFS respectively to abbreviate the terms.

Makes more sense to me than using a code that was devised to facillitate morse transmission.

However, the quite 'tight' definitions to do with the Q code are certainly a good thing eg QDM contains the information about the reference system used ie deg. Magnetic.

[This message has been edited by Tinstaafl (edited 18 December 2000).]

[little red train]

does anyone know where the H8Ll they got QUJ then?

[3 green's]

I agree, not the finest of descriptions but in the law books for the moment...

anybody have any thoughts on the original question ?

cheers

Paul

[BIK_116.80]

Tinny, could you please explain the derivation of the term "QDR". In particular, the "R" part.

[Tinstaafl]

Christ, I'll have to dig out my ATPL nav books. Haven't looked at them for over a year.

It may be R = Radial, but that Q code may be referring to VORs? Don't know until I look it up. No wonder I prefer 'common sense' abbreviations!

I'm off to Oz tomorrow for Xmas so it'll have to wait until I'm back in mid-Jan.

Sorry!

[BIK_116.80]

So, is there a majority - BAN the use of Q code?

And while we are at it, lets agree to discontinue the use of other quaint local RAF procedures as well.

[411A]

Generally too much QRM here!

[Bob Hawke]

Thats why they call QNH, Hectopascals. It's just a French conspriacy.

[AMEX]

Quite few years ago now and during my PPL, I was explained about QDMs&QDRs. What a confusing way to teach about a Radial. Anyway later someone showed me the light ;) and I have since, used radial and when I came across people trying to get their head around VORs and NDBs, I, this time showed the light by preaching the good word. RADIAL, RADIAL, RADIAL!!!! That's what it's called and that what it is.

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If you can't save the engine...save the airframe :)

[Dragger of Tail]

Yes, but which is the best way to intercept the radial to or from the station using a fixed ADF card?

[BIK_116.80]

Lets say your aircraft has a directional gyroscope, "DG", and a fixed card ADF.

Firstly, ignore all the compass numbers on the ADF indicator card as they are near useless. The ADF indicator index markings are quite usefull - the ones at 45 degrees, 90 degrees etc.

In your mind, transpose the ADF indicator needle onto your DG. Read off the number under the TAIL of the ADF needle and you know which radial you are on from the NDB site.

[Air Conditioned]

AMEX

Re RADIAL RADIAL RADIAL
WRONG WRONG WRONG

The term Radial applies only to a VOR.

The equivalent using NDB/ADF is a Bearing which may be From or To.

Do not use Radial incorrectly as ATC must assume you are operating on VOR. It is common for there to be an NDB with the same name at an airport, but quite likely to be at a significantly different location.

[lineup]

Easy way to remember- QDM -come to Mummy, going HOME! OK :)

[AMEX]

Point taken Air conditioned http://www.pprune.org/ubb/NonCGI/frown.gif

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If you can't save the engine...save the airframe :)

[thermostat]

Here is the formula you wanted.
If your present/desired bearings are within 60 degrees , then :-
Inbound: desired bearing, present bearing plus 30 degrees (in that order).

Outbound: desired bearing, 45 degrees, present bearing (in that order).
If more than 60 degrees, then go direct to the station.

As far as outbound bearings and radials are concerned they are both the SAME. They both radiate out from a point. When tracking outbound fron an ndb to the threshold it is far better to use "desired radial" and say to yourself -"what radial do I want, What radial am I on" and simply turn towards the desired radial. This is a fool-proof method of tracking regardless of the wind, and will prevent you from turning the wrong way (which is the biggest problem with tracking to the runway with a crosswind using that "bearing" method).
Hope that helps you. Merry Christmas.

[Royan]

The simple way is , you know your present and required QDM or QDR so remember this :-
QDM - required more steer less
required less steer more
example : you are on QDM 010 and you want to intercept QDM 020 so you have to take a hdg to the left to intercept.The hdg would depend on distance from station and how fast you want to intercept and remember to correct for the wind .
QDR - req more steer more
req less steer less
you have to be oriented at all times to avoid any confusion , but this simple rule works.

[Code Blue]

Dragger of Tail:

Perhaps a specific example would help (fixed card):-

EG. to fly along inbound on a bearing 270 from NDB assuming a/c to west of station. Also assuming you have tuned and positively identified station.

1. Turn a/c to mag heading of 090 - the reciprocal of 270 to point to the ndb.

2. observe ADF. The needle will point either left or right unless you happen to have a bearing from the station of 270.

3. turn 45 deg towards needle and fly until the adf needle points 45 deg towards the opposite side of the face of the dial.
You are now bearing 270 from station.

If you turn to 090 and fly that heading in a no wind situation you will track to the station. A cross wind will require bracketing to compensate - a whole other lesson :)

Draw it on a piece of paper. Imagine the arrow of the adf is attached to the ndb with a long piece of invisible string.

Does that help?

(editing for alcohol induced dyslexia)


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[This message has been edited by Code Blue (edited 26 December 2000).]

[This message has been edited by Code Blue (edited 26 December 2000).]

[Gary Halliday]

Biccy,
How do you transpose the needle when you are using a strip DI ?. I find the + and - hdg/QDM/R method works in this case, otherwise transposing is a good crosscheck.

I`ve always assumed that the R in QDR referred to reciprocal. Unlikely that it came from radial since they weren`t invented then.

I don`t imagine many atcos will get too confused if you say you`re on a radial from an NDB I think they`re usually aware which beacons on their patch are A1 or A8.

Q code never caused me any grief but I`m a Luddite. Stupid is a stupid word.

[have another coffee]

1) enter NDB ident in SP
2) LS 1L (LEGS page)
3) Execute
or (optional)
4) enter intercept course in SP then LS 6R
5) LNAV
6) order coffee (with a little sugar please)

easy ehhh?
After my CPL exam can't remember doing an intercept anymore. And that's the reason I sleep so well since then.

[Dragger of Tail]

Thank you, the original question was asked by 3 Greens, but I definitely learned something new.

[LetsFetz]

Try this: QDM=required-head-intercept
QDR=tail-required-intercept

Transpose needle to DG ...

To intercept a QDM:
from "required"(QDM) on your DG >>> go past the "head" (needle) >>> to find a suitable "intercept" heading (on that side)

difference between required&head should approx. equal difference between head&intercept ... round up/down to closest 30/45/60/90
Note: obviously when the difference is greater than 90, you are on the wrong side of the station ... thus you have to fly the reciprocal until past the station

To intercept a QDR:
from the "tail"(needle transposed onto your DG) >>> go past the "required" QDR >>> to find a suitable "intercept" heading

Same difference-rule as for QDM

Ignore the fixed card, think numbers later and double-check once you are on your intercept heading

Remember: there is only one way, the head of the needle moves ... DOWN !!! ... where ever you are or go (except of course when you are actually flying a QDM/QDR)

Watch it: I saw guys getting to comfi with this method, actually neglecting their situational awareness !!!

Happy New Year
Cheers and Beers
LetsFetz

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Let there be cold beers on a hot day !!!

[BIK_116.80]

Gary Halliday, I think you may have been addressing me.

I have never flown a civil transport jet with a strip DI as its main heading reference.

Now, when you say "Unlikely that it came from radial since they weren`t invented then" are you perhaps referring to VOR radials?

I think there may be some confusion between the radio theory use of the word "radial" and the common every day and navigation first principles meaning of "radial".

We all know that the radio signal transmitted by a VOR ground station is different in each different direction from the station. This of course is in contrast to the signal being transmitted from an NDB ground station where the signal is the same in all directions, hence the "ND" part of "NDB" standing for "non directional".

So you might suggest that since NDBs transmit the same signal in all directions that on a radio theory level they do not in principle use unique "radials".

But I would advocate a more common sense approach - which also happens to more neatly fit in with navigation first principles. I refer to a popular dictionary,

"RADIAL : like a radius, branching from a common centre"

and

"RADIATE : to emit rays, to spread out as if from a centre"

In a navigation context I could offer a definition of radial such as "an imaginary straight line starting at a defined position and continuing forever in a defined direction". Note that this could refer to an NDB - or a VOR - or any known point on a map. Sometimes this might be called a "position line".

The benefit of using the term "radial" when talking about NDB navigation is that there is no confusion about bearings being TO or FROM, radials always being FROM the ground station.

I do not know what the "R" in "QDR" was originally meant to stand for (if anything). I am aware that the Q code was designed for a time when morse code was king and the Germans were the enemy. These days it seems more like the internet is king and the Germans make all the best cars.

[LetsFetz]

???

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Let there be cold beers on a hot day !!!

[Gary Halliday]

Yes BIK_116. (Where is that?).
I was addressing your comments.

1. Who said anything about civil transport jets ?. Mine doesn`t have a fixed card ADF either but I would suggest that if you`re still grappling with the theory of intercepting QDMs and QDRs when flying a civil transport jet you`re in the wrong job.
Some civil transport aircraft still do possess strip DIs though not as a primary reference - that would be the P type compass (with mirror). I flew one not that long ago - certainly more recently than when Bill Dodd and I did it in black and white.

2. My bit about radials actually agreed with your use of the term - I wouldn`t quibble. How would you do "Radial radial radial - XXX request radial"?.
" XXX what kind of radial would you like - a QDM or a QDR ?".
Anyway the best sort of radials have cylinders.

3. I was only getting hooked by your anti Q code thing. Personally I enjoy the strange and arcane terms we use - not for the bafflement of the poor proles who don`t have the faintest idea why we fly - but because they`re fun. However I do admit to having enjoyed the ATPL theory, and thinking that we should all use sextants.

4. I think 3 greens has got his answers but as usual they would probably be best drawn on a piece of paper.

Gazza.


[This message has been edited by Gary Halliday (edited 01 January 2001).]

[This message has been edited by Gary Halliday (edited 01 January 2001).]

[This message has been edited by Gary Halliday (edited 01 January 2001).]

[BIK_116.80]

Gary, I will agree to use a sextant for all my navigation if you will agree to never use the Q code again.