Those Errors!!!
 

Hi folks!

Hope someone can give me a hint, how to learn this turning or acceleration errors of the compass?!?

How did you get it right?

I too had troubles with this, but I found that reading one line, understanding it, before moving onto the next line of text helped! First time I read through it I couldn't relate the diagrams to the text at all. The next time, I took one line at a time and compared it to the diargram, understood it, and then moved onto the next line.

Also! Remember to rotate the page whenver it says so! It always helps. Fair enough if people start laughing at you in the exam but at least you'll get it right! lol. I am sure everyone will be "rotating" in the exam.

Remember, read it, again, again, and again, that's how I did it. TRy and make yourself a Menmoic as well (spelling? you know what I mean!).
:}

I ended up using a pencil and my crap5.

I would set it up and then work out which way it would turn etc.

Mind you both methods are pretty useless in real life.

Bouncing around with a partial panel trying to figure out whats happening with the compass. Timed turns are the way forward.

MJ

Couple of things that saved me:

The instruction mnemonic UNOS for the Northern hemisphere - Undershoot North, Overshoot South (you should undershoot the desired heading on any northerly headings (from about 280 - 080 degrees) and overshoot the desired heading on any southerly headings (from about 100 - 260 degrees)). Sketch a compass rose and think through the turn. Of course it is ONUS in the Southern hemisphere.

Acceleration causes an apparent turn toward the nearer pole.

Oh, and liquid swirl increases the undershoot, so reduces overshoot. Hence it increases the turning error through North and reduces it through South.

Turning:

UNOS - see Send Clowns perfect explanation


Acceleration:

ANDS - (Northern Hemp) Accel North Decel South

Got me a high 80 in Nov's INS paper and there were surprisingly few Gyro questions in the exam.

Good luck with 'em.

MB

A feedback question from the January exam:

You are performing a compass turn to starboard in the northern hemisphere from 135 to 225. At what heading do you stop the turn?

225
220
210
240


UNOS tells us to overshoot when turning through South and the only overshoot answer is 240.

I and others got this wrong in the exam despite knowing UNOS and ONUS simply because our first thought was of the compass overshooting and needing to be halted early, rather than the aircraft which has to overshoot after which the compass will settle back to the correct heading.