MECIR: ADF Intercepts

[50.40.30.20.10]

Hi,

I am interested to know if anybody has any tips on methods to use for ADF/NDB intercepts, I can do them just fine when written on paper, but establishing a method to 'mentally' do those is proving difficult. Would love to hear some advice on a simple, yet effective method for completing these without having to devote too much of the limited flight time thinking about it.

Cheers

[The Green Goblin]

Do not over-complicate it.

Outbound to inbound, take the long way around.

The head wall fall.

The tail will rise.

In other words, if you need to track say 270, and it is to the left of the lubber line (285), and the head of the needle is to the right (300), you need to get the head the needle to the left. Picking any heading (anything further than 316) further right will place the head of the needle to the left and allow you to 'drop' it back onto 270 (the head will fall).

The opposite is true for tracking outbound. You need to make the tail 'rise' to your required track.

I used to overthink it from Bob Taits HAT trick, however this is only required for theory. In reality you don't even think about what angles or headings or tracks are needed, you just try and drop the head onto the right track, or let the tail rise onto it.

I hope I helped!

[Ex FSO GRIFFO]

Can only suggest forming the 'mental pic' of where you is, vs what is required.

I used to think of The NDB as being at the end of a piece of string - in the direction of the ADF needle of course - and I was attached to the other end.
VERY 'basic' I know, but it helped to form the mental pic. in the early days, and then you just seem to get used to it...

The rest is 'mental gymnastics'.....and keeping a 'weather eye' (w/v) on 'the needle'....
And not to get 'too close' to the aid. By giving yourself some 'room' to manoeuvre, you won't find yourself flying around the darn thing without being able to fix 'station passage' over it.
Like I said - VERY basic - is this what you were after??

Cheers

[Xeptu]

EASY, picture that needle over the DG, then it's an RMI, the tail end of the needle is where you are, since you know where you want to go, pick an intercept angle and go there.

[Capt Fathom]

Have you tried any online NDB simulators (http://www.luizmonteiro.com/Learning_ADF_Sim.aspx).


And as Old Akro below mentioned, this one (http://www.visi.com/~mim/nav/) can be downloaded an runs offline!

[UnderneathTheRadar]

Imagine that you 'live' on the tail of the ADF.

If you're inbound then to move the head to where it needs to be means looking at the tail and say I need to turn left to get the tail to move right.

If you're outbound then the tail is at the top and you can just turn in the direction you need to get the track you're after.

[Kharon]

IMHO the best orientation tool is usually strapped to your left wrist For practice, every time you look at your watch, work out what the inbound and out bound track is for each pointer; e.g. 0900 = 360 outbound (180 inbound) and 270 outbound, (090 inbound). NDB is in the middle of course.

Once you know where a 'track' is the rest is a doddle. I am 050 inbound, where is 360 inbound, the shortest arc is etc. It used to be called orientation, new speak = situational awareness. Don't go IFR without it .http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/thumbs.gif

[training wheels]

Practice on a computer based simulator ... MS Flight Sim X is very useful for this kind of thing. This was suggested to me by a reputable, highly respected and long established MECIR flight instructor and ATO at Moorabbin. You'll get used to them very quickly and will save you a lot of time and money in the air.

[Old Akro]

I agree that SIM time is really worthwhile. X-Plane is better (and cheaper) than MS FS. There is also a useful little (free) adf simulator that you can download. I forget its name, but a bit of googling will find it.

[desert goat]

Google Tims air navigation simulator:ok:

[PA39]

The Green Goblin has the trick!:ok: use the KISS principle.

[Capt Fathom]

The Green Goblin did have it, but then he ruined it by having to explain it! :}

[AerocatS2A]

All I've ever needed to know about it is that I have to chase the head of the needle and lift the tail up.

[QSK?]

I just rely on the acronym IOOS: i.e. Inbound Opposite; Outbound Same.

If inbound to the NDB and the new bearing required is right of our your current bearing, turn left to intercept (inbound opposite).

If outbound from the NDB and the new radial required to be intercepted is right of your current radial, turn right to intercept (outbound same).

Hope that helps.

[Chimbu chuckles]

Jesus-I had to read some of the above posts 2 or 3 times:ooh:

Imagine the center of your DG is the NDB. You're tracking 270 TO the NDB and you want to track 300 to the aid. It's very easy to picture your aircraft in the bottom of your DG tracking toward the NDB that is the center of the DG and it will be easy to picture which way to turn to intercept the new bearing to the aid. If you're tracking outbound it's equally easy to imagine your aircraft at the top of your DG traveling away from the aid and see where the new bearing is in relationship to the current bearing.

Going from inbound to outbound (without station passage) or outbound to inbound is just as easy to picture in your mind.

God's eye view if you like:ok:

[Dangnammit]

OIL- Outbound to Inbound, Long way 'round.
Heading outbound and the track you want is on the bottom right hand side of the DG, turn left (ie the long way around).

IOS- Inbound to Outbound, Short way 'round.
You're inbound and want to take up an Outbound track on the right hand side of the DG, turn right (ie, short way around).

Inbound to Inbound- you want to take up a new inbound track that is on the left of your current track, turn right (ie opposite to position of track on DG. Remember the centre of the DG is the aid.)

Out bound to Outbound- Turn towards the new track. Again remember the centre of the DG is the aid.

[AerocatS2A]

i.e: you are tracking on the 280deg outbound and want to intercept the 160deg inbound.
Does this ever actually happen in real life? Apart from doing a teardrop approach where it is all spelled out for you in black and white anyway, I've never had to track from some outbound bearing and then turn to some other inbound bearing.

I had been trying to analyse how I work out intercepts for NDB tracks and couldn't come up with anything better than "I just sort of do it", but Chimbu Chuckles has eloquently described exactly how I cope with any maneouvering reference to an NDB (or any other aid).

[ForkTailedDrKiller]

Does this ever actually happen in real life? Apart from doing a teardrop approach where it is all spelled out for you in black and white anyway, I've never had to track from some outbound bearing and then turn to some other inbound bearing.

Was having the same thought. Its time the training environment caught up with reality.

I had been trying to analyse how I work out intercepts for NDB tracks and couldn't come up with anything better than "I just sort of do it",

Yes, that is SOP for Forkair. 20+ renewals would indicate it works.

Maybe I am a visual sort of person, but reading these posts means nothing to me. Go do it in a sim or an aeroplane, and don't worry too much about it.

but Chimbu Chuckles has eloquently described exactly how I cope with any maneouvering reference to an NDB (or any other aid).

Agreed!

Dr :8

[denist]

I just remember "Head down, Bum up" easy to remember good old Aussie saying.

[bentleg]

If you are uncertain where to head for an intercept, turn to the desired heading, the needle will then tell you whether you need to fly left or right to intercept.

If you are going towards the NDB, the needle then needs to be put on the other side of straight ahead when executing the intercept. With practice you can work out a heading to intercept by looking at the dials.

[ballistix71]

Personally I never had an issue with transposing the ADF needle when I learnt to do intercepts. I was taught all the rules etc originally but it wasn't until I actually did my ME-CIR that I was taught the method below.

The DI can be used as a map like a few of the others have said. The center of the DI being the station position and the tail being the aircraft position. Before I go on, I'll just clarify a point that will come up;

QDM = track to the station
QDR = track from the station

It's what I use currently so I hope it doesn't cause confusion.

eg:
http://i1087.photobucket.com/albums/j478/jetdriver71/NDBIntercepts.jpg

Tracking 360 QDM (ie to the station)

If you wanted to intercept a QDM of 330 then you would walk through the 4 steps you most likely have been taught already.

1) Where am I?
-> transpose needle you are on the tail position

http://i1087.photobucket.com/albums/j478/jetdriver71/NDBIntercepts-Step1.jpg

2) Where do I want to go?
-> Set HDG bug to Track or find it visually. In this example you want to track 330 QDM.

http://i1087.photobucket.com/albums/j478/jetdriver71/NDBIntercepts-Step2.jpg

3) How do I get there?
-> Divide the DI in half through the track you wish to fly (QDM or QDR it doesn't matter). You then choose an intercept heading which is on the opposite half of the DI to the aircraft position determined from step 1 within 90 degrees of the desired track. Any intercept heading that passes over the station will result in you intercepting track overhead (eg HDG 360).

http://i1087.photobucket.com/albums/j478/jetdriver71/NDBIntercepts-Step3.jpg

Notice that a heading of 330 to 360 will intercept the track after the station or overhead the station and is not going to be acceptable so you would need to do an intercept greater than 30 degrees. (Edit: Highlighted headings of 330 through to 060 not showing up when previewed but that is the range of headings you would be looking at for the intercept).

4) Is it working?
-> Turn onto the intercept heading and check to ensure that either the head of the needle is dropping toward the desired track or the tail of the needle is rising to the desired track.

Just remember always turn the shortest distance to your intercept heading that you select (removes the need to remember the OIL mnemonics).

Now this is only one method of doing the intercepts and it may not be the best for you. Others have mentioned the parallel track method (turn onto desired track and see which way needle points) and the basic transposition and rules methods (OIL etc).

The method above works for both QDR & QDM intercepts and I find it easy to apply quickly. Just remember if all else fails get above your minimums and re-orientate yourself. Better safe than sorry.

Hope it helps

[The Green Goblin]

GG i like the sound of your method, but i dont quite understand it from your post, could you perhaps explain it in a little more detail with the aid of an example.

i.e: you are tracking on the 280deg outbound and want to intercept the 160deg inbound.

I'm not going to get to fancy with pictures etc.

As Chuck said, imagine the centre of the RMI/ADF is the aid and you are on the tail. If you are outbound on the 280, and you want to go inbound on the 160 have a look at the situation. 160 inbound is actually the 340 bearing from the station, which is to your right. Pick any heading 90 degrees to the right of 340 and adopt one. Once the head of the needle is within 5 degrees of pointing 160 inbound, turn onto the heading. Use the drop the head method for accurate tracking on your inbound track.

GG