Teaching IF

[cross feed]

I am new to this site and completely new to teaching IF. I would appreciate any help one could give me on how to get started to teach IF, more specifically teaching how to fly a fixed card ADF. I can fly it but to teach it is another ball game.
I understand the RMI/HSI is easier, but the basics of tracking/drift associated with the fixed card will be helpful.

:O

[Captain Jock]

Perhaps I am missing something but should you not have covered all this on your instructor course?

[nimbostratus]

:rolleyes:

[FlyingForFun]

In the absence of any sensible answers:

Before starting on the techniques, cover the equipment: the NDB, the ADF and the RBI. Include in this all the various errors in the equipment, especially emphasising the typically short DOC of NDBs, and the fact that the ADF is not reliable in turns. (There's no need to cover ADF dip for the IMC rating, although it is required for the IR.)

Once that is done, look in detail at the instruments. Draw an RBI, and split it into the top and bottom half. Tell the student to ignore the bottom half. (This assumed you're going to teach tracking from the beacon using the tail, not the head.) Then, split the top into a left hand segment and a right hand segment. The left hand segment is -ve, the right hand segment is +ve.

Now, draw an NDB in the middle of the board. Draw aircraft in various positions around the NDB, some pointing roughly towards it, others pointing roughly away from it. For each example, draw what the pilot would see on the DI and on the RBI. Teach how to find out what bearing the aircraft is, either to or from the beacon, by adding/subtracting the RBI reading to the DI reading.

Next, teach "push the head". Draw a line, east-west, through your NDB. Draw an aircraft, slightly north of the line, to the east of the NDB, heading westbound - in other words, tracking towards the beacon on the 270 QDM, but north of track. Draw the DI and the RBI. Draw the same aircraft, closer to the NDB but still north of track by the same amount. Draw the DI and the RBI again. Point out how the head of the needle has moved away from the "top" of the instrument, in other words the "top" of the RBI will "push the head". Show how, if the aircraft continues past the beacon, the needle will point behind the aircraft, and if it continues on its current track, the top of the RBI will "pull the tail".

Now, teach tracking to the beacon. First of all, in still wind, draw an aircraft "on track". Show what the DI and the RBI look like, on track, in still wind. Now, add wind, and draw the aircraft, still on track, with enough drift to counteract the wind. E.g., 15 degrees of drift from the north, the heading will be 285 (versus a desired track of 270). Show how to compare the current heading with the desired track (i.e. 285 vs 270, giving a "relative heading" of +15). Show how the RBI reads equal but oposite, i.e. -15. Explain that this equal-but-oposite relationship always indicates that the aircraft is on track. You could also expand this to include the pictoral relationship between the two, i.e. the RBI needle is pointing at the desired track. Be sure to point out the markings at the top, bottom, left and right, and also the 45-degree markings, on the DI and RBI, and their use in comparing the two instruments when doing it pictorially.

Once the student understands what the instruments look like when on track, deal with the off track scenario. Again, start with no wind, and draw the aircraft off track. Show that, if it maintains the current heading, the RBI will "push the head" in the oposite direction to where it needs to be moved to. In order to correct that, you have to turn the aircraf through the needle so that the RBI will "push the head" in the correct direction. Show what the RBI and DI will read when on a good intercept heading, and what they will read when the intercept is complete.

Now, put in a nice strong cross-wind, and deal with the situation where the aircraft is off track, on the windward side. Show how exactly the same correction will work as worked in still wind.

Next, put the aircraft off track but downwind. Now, show what happens if you don't put enough correction on. E.g. 20 degrees of drift, 5 degrees off track. Turn the aircraft 10 degrees into wind, onto a heading of 280. With 20 degrees of drift, the aircraft's track will be 260, in other words, still diverging from track. It appears from the RBI that the head of the needle will be "pushed" in the right direction, but actually this is not so, because it's not actually the top of the RBI (the current heading) which pushes the aircraft, but rather the aircraft's track. Stress how important it is to turn into wind sufficiently. Turn into wind by the drift plus the amount by which you want to attack the desired track.

Finally, repeat the whole thing with tracking from the beacon. Additionally for tracking from the beacon, point out the case where you parallel the desired track, the RBI seems to be pulling the tail of the needle in the correct direction but it will never actually get there.

All of this should be done as a long briefing, to be followed by several flight exercises to practice the techniques.

Hope that's of some help. It's a big subject to express fully in a short message, so you'll need to flesh it out yourself.

FFF
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[hugh flung_dung]

You need to get them to build a "god's eye view" so that they can think, rather than just driving the dials - so I disagree with a few of FFF's points.

First point: avoid sums! There's no need to add/subtract RBI indications to/from headings. Get them simply to visually transpose the RBI needle on to the DI. This is easier than doing sums, as accurate as you want it to be, and is the same as using an RMI.

Next point: start by getting them to position fix (by reading the tail overlaid on the DI), then working out how to get to the beacon, then how to intercept tracks.

Next point: make sure they always know where the wind is, have an estimate of max drift and how the proportion of MD varies with relative angle.

Personally I don't like the push/pull approach, but lots do. I ask people what their track is and what track they want. If you're going "away" and want a bigger number you turn right (onto a planned heading, not randomly) - if you're going "towards" turn left for a bigger number.

Other points: Use the head when tracking "to" and the tail when tracking "from". Always leave the rotatable card "zero'ed". The head always falls and the tail always rises. Dip is easy to understand and the stude needs to know about it to understand what's happening - just teach it as the needle "falling" by half the bank angle.

HFD

[foxmoth]

Like HFD I prefer to transpose the needle, but always use the head of the needle - if the head is to the left of your required track it is a turn left indication if to the right a turn right - a lot like flying a VOR and very simple, if you want to PM your email I can send you an article I have on how to do this. Also, if you have internet where you teach I would recommend http://www.luizmonteiro.com/Learning_ADF_Sim.htm
just put your mouse pointer on the aircraft and you can change heading and move it around seeing how the needles move,this is a LOT easier than chalk & talk.:ok:

[cross feed]

I do thank all for for their generous contributions to my question. I am sure these tips will enable me to understand it a little more,:ok: to then be able to teach it better.

Much appreciated