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piecrust

Compass swing

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Have just installed new compass in plane. My swing is out 30 degrees when positioned at 120 and 60. In reads true at east and west. Can it be changed without throwing out the magnetism of east and west?

 

N=340, 30=360, 60=30, E=95, 120=150, 150=180

 

S=210, 210=235, 240=250, W=273, 300=290, 330=315

 

I have read the casa bulletin from 2007. Adjustment in layman terms is required.

 

 

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That is an awful long way out. Could you reposition the compass or see if there is something highly magnetic that could be moved.

 

It may be possible to do the adjustments, but I think your corrections would be fairly large.

 

You don't say what type of aircraft it is fitted in, steel tube fuse or plastic?

 

 

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Aluminium, Tecnam echo classic. I never use the thing but by law it's required. Between my digital heading, GPS and oz runways it's almost redundant. From what I read a correction of 20 deg is only available. Also a turn of 180 degrees with adjustment screws only. It is located directly above the radio and transponder. I feel that between the two they are causing the deviation.

 

 

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About 150mm minimum is the recommended distance from a Compass, from memory.

 

 

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Piecrust's compass and mine might be twins- their deviations are so similar. I spent lots of money having mine serviced, but it's so far out as to be near-useless. It's not mounted near metal objects or other obvious sources of interference.

 

Maybe it's a northern hemisphere compass.

 

 

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What does the compasss read when placed on the ground away from any hangars and aeroplanes. You need to establish if the problem is internal or external (to the compass)

 

.

 

 

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Yes compass is chinese made. However I did specify for Southern Hemisphere. It is unsettling that I do have a calibration document with it but it has chinese writing on it. I have drawn it all out on paper and there is a pull towards WNW that is very consistent. East reads true but after that it wants to swing away. Next port of call will be to remove dash and compass and place on compass rose alone, either that or fly west only.

 

 

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Piecrust's compass and mine might be twins- their deviations are so similar. I spent lots of money having mine serviced, but it's so far out as to be near-useless. It's not mounted near metal objects or other obvious sources of interference.

Maybe it's a northern hemisphere compass.

Nice to hear someone Else having the same experience

 

 

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Maybe it's a northern hemisphere compass.

My first thought

 

PHIL.

From what I have read it wouldn't have those symptoms. Compass dip is caused by using incorrect hemisphere. Needle weight is affected and you will get drag.

 

 

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Piecrust's compass and mine might be twins- their deviations are so similar. I spent lots of money having mine serviced, but it's so far out as to be near-useless. It's not mounted near metal objects or other obvious sources of interference.

Maybe it's a northern hemisphere compass.

Mine was fitted to the aircraft prior to 2004, and appears to be American.

 

 

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Will check against old compass deviation card when I get back to the hangar. Interesting video.

 

 

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The only difference between northern and southern hemisphere compass is a little dob of solder to keep the pointer disk level.

 

 

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The only difference between northern and southern hemisphere compass is a little dob of solder to keep the pointer disk level.

...you mean I don't have to stand on my head to read it?

 

 

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...you mean I don't have to stand on my head to read it?

No it's a myth, only a weight difference on pointer

 

 

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...you mean I don't have to stand on my head to read it?

If you do, make sure that your feet are positioned to the sides of your scull (just above the ears) or your bent up legs will obscure your view.008_roflmao.gif.692a1fa1bc264885482c2a384583e343.gif

 

Alan.

 

ps My wife is good at this.

 

 

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Definitely non ferrous mounting screws?

Didn't think about that, they are steel with steel nuts under the dash. Nice jab by the way, remember reading the write up a few years ago.

 

 

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I have a GPS receiver roughly 150mm away from the compass mounted on the dash. This runs my directional indicator on ADI. It has roughly 2m of spare cable wound up and cable tied under the dash. Could this induce a magnetic field strong enough?

 

 

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I had similar compass errors recently when I fitted a standby compass to the top of the combing panel. I only fitted it because my precision vertical card compass must have slipped a cog or two and started reading about 70 deg out. It was mounted at the top centre of my panel. After a few compass swings, I couldn't get any accuracy with the standby compass. I decided to remove the vert card unit as it was no good anyway and tried another swing, I now have very good accuracy at all points. The vert card unit had a significant effect on the standby compass and was mounted about 25 cm away from it.

 

 

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Guest Andys@coffs

Does your gps have a speaker? Some Garmin ones do???!!

 

If it does and it's within a metre of the compass you'll have compass issues, any other instruments with speakers same thing.....Garmin should know better!! Speaker = bloody big magnet

 

Andy

 

 

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Does your gps have a speaker? Some Garmin ones do???!!

If it does and it's within a metre of the compass you'll have compass issues, any other instruments with speakers same thing.....Garmin should know better!! Speaker = bloody big magnet

 

Andy

Yes my GPS has a speaker and its 300mm away. Garmin aera 500. Never would have thought of that. Surely the speaker magnets would be to small to effect? Then again a headset can throw it out a mile

 

 

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