Teaching the ADF

[AV8 consultants]

Over the years I have been taught several ways to use the ADF effectively whilst navigating. Now I'm faced with having to teach my student. The book explains the theory well but the student always has a hard time of grasping the principle of practical use. Does anyone know some really good tips of tricks on how to make the picture clearer. i.e intercepts, where they are in relation to what the ADF says etc. All replies would be most welcome.

[Oz_Pilot]

Basic orientation: transpose needle from ADF to DI and get tracks to and from the station.

For all intercepts: first ask "do I have a solution?" i.e. will the head fall or tail rise onto the required track?

Inbound: set up a heading so that the *head will fall* onto the required track. Turn to a heading past the current track to the station to set up an intercept. (i.e. turn from current heading, to current track inbound, and through to an intercept. From it, to it, through it)

Outbound: Easier (a little...) because you don't have to make the intercept by the station. Turn so the needle will rise to the required track, if it isn't already set up to do so.

I've found (in limited experience I will concede) that keeping it simple then developing familiarity works better than trying to get a complex method (i.e. mathematical) to work - flying then deteriorates and makes the whole job much harder.

[Vigilant Driver]

Like you AV8, I have had the ADF taught to me in lots of ways. OZ, yes for working out your QDM back to the beacon then transposing the ADF needle works a treat and keeping it simple is the ticket!

I’m currently using the following method with my IMC student. It works for him.

Point 1: If you have got a moveable card to the ADF dial up 360 at the top of the instrument. Now don’t change this and use it like a fixed card ADF

Point 2: The head of the needle always shows you which way to turn, so if it is left of 360 then you turn left, if its right of 180 then you turn right.

Point 3: The head of the ADF needle always falls down the face of the instrument

Point 4: To get on to a desired QDM to a beacon, turn the aircraft to that QDM and then correct as per point 5. This is a very PPL thing to do; CPL chaps should be turning straight to a heading to gain the inbound QDM. (ie. fly an aeroplane with an RMI). But this method works!!

Point 5: When you are flying your correct heading and the needle shows you an error, double the error in your correction to get back on your desired QDM/QDR, to/from the beacon.

Here are some examples to illustrate:

Inbound to a beacon on a heading of 100. ADF shows 5 degrees right (ie. 005 on the ADF). So to get on our 100 inbound QDM turn right 10 degrees correction, so that’s 110 to fly. We know that we are back on our 100 QDM when the ADF indicates 10 left (ie. 350 on the ADF). Now turn back to your heading to maintain the 100 inbound QDM.

And here’s another:

Outbound from our same beacon maintain a QDR of 100 (that’s a QDM of 280 ie the same ‘radial’ as in the previous example but outbound). ADF shows 5 degrees left (ie. 185 on the ADF), so to get back on our desired QDR, turn left, double the error giving 090 to fly. Now we are back on our desired QDR when the ADF indicates 10 left (ie. 190 on the ADF). When this happens turn back to your heading to maintain.

Point 6: If you get confused just change your heading to your desired QDM/QDR and then correct it as per point 5.

Point 7: Don’t forget to keep re identifying the NDB morse ident. CAA trappers love it when you do that!

This might all sound confusing, but once you have the concept it is easier to use in the air than that + - + - stuff.

If you’re still confused try drawing the above examples out.

Have fun,

Vigi


[This message has been edited by Vigilant Driver (edited 01 March 2000).]

[Jamjar]

CORRECT !



[This message has been edited by Jamjar (edited 01 March 2000).]

['I' in the sky]

Certainly agree about keeping the moveable card fixed. I recently picked up an IMC student halfway through his course. I can't count the number of times he moved that card as we tried to intercept the inbound leg of the hold. What's worse it didn't work out and we bust through every time.
Treat the DI as a moveable card that moves itself and saves the pilot a completely unnecesary distraction.

[AV8 consultants]

Can't believe I'm replying to my own post but hell someone else might benefit.
I have spoken to a few old and bolds and they tell me that there is 3 things that help;
1. Your aircraft is always on the tail of the needle and it is trying to pull the tailof the needle itself.
2. Your aircraft on the tail of the needle is always heading up the DI or ADF.
3. The station is always in the middle of the ADF.
I have gained soooo much from that invaluable info, hope it helps others too. :)

[2R]

Check it out
http:www.visi.com/~mim/nav/index.html
All you ever wanted to know,have fun

[Vigilant Driver]

AV8,

Yes I've heard this business about playing around with tails. It works with an RMI when you push the head and pull the tail, but it can confuse the hell out of poor Bloggs.
Isn't it easier to say to Bloggs 'If the head point left you turn left, if it points right you turn right whether you are flying to or from the beacon' I find that most students understand that concept!

Throw away comment: You don't use the tail of the ASI needle for reading airspeed do you? Why use the tail of the ADF for reading relative bearings! :)

Safe beacon bashing chaps!

Vigi

[Hugh Jarse]

AV8consultants, you answered your own question.

As you correctly stated, you are always at the tail of the needle.

Without going into great detail (if you're not where you want to be): Turn as required to drag the tail of the needle where you want to go. Keep it simple.

[hugh flung_dung]

All this pushing, pulling and shoving sounds awfully rude chaps - and confusing to the stude.
The only time when this is critical is turning inbound to the hold or the final approach, at other times you've got time to think. The key is to keep asking yourself "what QDM/R am I on and what do I want?".

1. Forget the ADF card (or set it to 360)
2. Overlay the ADF needle onto the DI
3. If you're going away from the beacon read QDR from the tail, if it is less than you want - turn right
4. If you're going towards the beacon read QDM from the head, if it is less than you want - turn left.
5. The amount to turn depends on distance from the beacon, how fast you want to get onto a QDM/R and what the wind is doing.
6. Keep overlaying the needle onto the DI and asking yourself "what's my QDM/R and what do I want?", when the QDM/R is what you want turn onto it and allow for drift.

[Oz_Pilot]

We're all really saying the same thing, it's just a question of what will Bloggs listen to, hear and (most importantly) understand? Hence my inclination to KISS (keep it simple, stupid).

Also - PC sims can be good to develop familiarity, had one student who fly an hour of NDB intercepts on Microsoft Flight Sim and it helped him to understand how the ADF moved. Obviously wouldn't help everyone...

[Tinstaafl]

I usually found it slightly easier to teach VOR intercepts 1st. It seems to me to involve less mental integration than the ADF since the VOR provides a solution in terms of 'Where I am in relation to the aid', whereas the ADF is 'Where the aid is in relation to me'.

Once VOR skills are developing then go on to ADF Intercepts.

However, for both these devices, I found it easiest to develop a situational awareness (I know, an overused term, but...) about where they were, where the desired track/radial/bearing is, most expeditious way to get there etc., followed by rote rules that could confirm whether the decision making was correct.

I know this sound long winded, but I think it's a combination of all of the above. I know that when I'm using the instrument then I use a variety of methods depending on the situation.

At first I teach along the lines of:

1. the RMI (DI if RMI is not available) is akin to a god's eye view from above (insert preferred simily here) of the aircraft flying over the earth's surface. The outer edge of the instrument represents the furthest scale of the intercept problem eg currently located at 10 nm would like to intercept outbound at 20 nm --> then the circumference equates to 20 nm.

2. In this sense, the aircraft will ALWAYS be on the tail of the RMI needle, flying UP the instrument panel. If no RMI then use a transposed needle onto the DI. A pencil to represent the ADF needle can help here.

The aid will always be at the centre of the RMI / DI.

ergo, the tail of the needle is aligned with the brg FROM the station, the head of the needle the brg TO the station.

Using a finger (or whatever) point to the current position.

3. Point (on the RMI / DI) to the what track / BRG / radial is required (including whether towards or away from the station). This graphically shows where in relation the current position vs. desired position is.

4. Turn the shortest distance of arc to get there.

Steps 1 to 4 are good for orientation but how to confirm once turned that the solution is correct?

I see that this is where 'rule based' methods are advantagous. eg "the head always falls", "on an inbound intercept the head must fall (on the OPPOSITE side of the ADF instrument to the DI) to the difference between the current heading & the desired track.

Yeah, I know this one in particular SOUNDS long winded - blame English grammar :rolleyes: . It's rather more easier to show :)

Similar rules are available for other circumstances.

These are there as confirmirmations (or more importantly, as error traps) for the orientation & decision making process.

This all seems rathery lengthy http://www.pprune.org/ubb/NonCGI/confused.gif , but it's difficult to accurately describe what is essentially a demonstrative & pictorial process.

My $0.000002 worth (how DO I make a UK pounds sign using a US keyboard? http://www.pprune.org/ubb/NonCGI/redface.gif )

[Stan Evil]

I agree with Oz_Pilot. Some computer simulations can help a lot. Have a look at RANT on oddsoft.co.uk - there's a free demo that you can actually use.

[Charlie Foxtrot India]

Back when I was a very confused IMC rating student (when computer simulators were only found on Star Trek) my instructor simplified it all by putting some ropes on the ground to represent eight relative bearings, and I had to stick my arm out to represent the head of the needle while shuffling about intercepting various ropes inbound and outbound and in the holding pattern. Well it worked for me, provided much entertainment for the onlookers, and its a lot cheaper to be totally confused on the ground than in a holding pattern somewhere.
Personally I like to use the rotating card, because then the tail of the needle is always on your bearing from the station, without "double handling" by transposing it to the DI, ...but I admit it only works well if the stude can hold a heading on instruments, so get that bit right before you start playing with the ADF..

A silly question for the transposing needle to the DI folks....how can you do that on limited panel especially if the DI is spinning around like an old LP? Just a thought.

PS Vigilant Driver, I was taught that great circle bearings to an ADF were True, and that variation was applied at the aircraft, so therefore isn't the QDM actually a QUJ?



[This message has been edited by Charlie Foxtrot India (edited 05 March 2000).]

[Vigilant Driver]

CFI,

Yes you are correct. The ATPL nav exams have just come back to me like a slap in the face! http://www.pprune.org/ubb/NonCGI/frown.gif I shall in future bin my use of Q codes for the ADF and use maybe a 'track to/from the beacon'. Probably better for Bloggs as well.

Whilst we are on the subject of PC sims for NDB/VOR nav here's a freebie I found on the web and often use with my students. It's good because it is so simple and students can try out methods to see which is best for them without burning avgas!

Find it at http://www.visi.com/~mim/nav/

And I should just say thanks to the author Tim Carlson who has done a great job with this!

Vigi

[This message has been edited by Vigilant Driver (edited 06 March 2000).]

[avguy]

I'm a needle to DG transplanter.
I use the DG as a map in my head the centre being the station and a/c on tail of needle tracking up DG. then I ask 5 questions
Where am I?
Where do I want to be?
Which way do I turn to get there?
What heading do I turn to?
How will I know when I'm there?

Not only is the dg mind "map" used to work out where you are but also where you are in relation to where you want to be and thus the direction of turn os obvious.

If you go through the questions diligently each time its fairly hard to screw up (still possible tho!!!)

[mustafagander]

Back in the good old days when I was trying to suss the ADF I was taught the 3 basic rules:-
1/ the NDB is permanently fixed to the head of the needle
2/ the a/c is permanently fixed to the centre of the needle
3/ all you can ever do as a pilot is drag the tail of the needle around the dial
As for orientation, figure what quadrant you're in (NE, SE etc) then what quadrant you want to be in, eg to intx 180 to the NDB you need to be in the N quadrant, then turn to make it happen.
I too can't do the sums to make the mathematical solution work.