Adjusting the KA 51B Slaving Meter
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Adjusting the KA 51B Slaving Meter
Hi,
The HSI on a plane I fly is about 20 degrees out (sometimes!) and I am not clear how to re-align correctly.
The manual says you switch to the 'Free' mode which is fine. then...
2 Questions...
1) Do I then do a clockwise/counter clockwise adjustment based on the 'Slaving Meter' or the aircraft 'Compass'?
2) Why wouldn't I just adjust to the Compass in which case what is the point of the Slaving Meter which needs to be centered?
Thanks for any advise.
The HSI on a plane I fly is about 20 degrees out (sometimes!) and I am not clear how to re-align correctly.
The manual says you switch to the 'Free' mode which is fine. then...
2 Questions...
1) Do I then do a clockwise/counter clockwise adjustment based on the 'Slaving Meter' or the aircraft 'Compass'?
2) Why wouldn't I just adjust to the Compass in which case what is the point of the Slaving Meter which needs to be centered?
Thanks for any advise.
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Generally, the remote compass is more precise than a direct-indicating one, provided both are operational. I do occasionally see my HSI fall out of alignment, so I just turn the slaving off and back on while flying straight and level. It resynchronises automatically within a few seconds.
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If it is only out sometimes it sounds like you need to swing the compass, I am going to guess that you will find some sort of magnetic interference near the flux detector
Last edited by A and C; 5th Oct 2012 at 22:38.
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The alignment (compass swing) of an HSI involves both rotating the remotely mounted fluxgate magnetometer, and adjusting the KA51B.
20 degrees is quite a lot. I wonder whether somebody has removed the magnetometer (KMT112, usually, on a King system) and put it back in a different orientation?
Or maybe a wire has come off somewhere....
20 degrees is quite a lot. I wonder whether somebody has removed the magnetometer (KMT112, usually, on a King system) and put it back in a different orientation?
Or maybe a wire has come off somewhere....
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20 ° is way out of my limits for an HSI to be used under IFR, even if the deviation card for the HSI should show it (which I really doubt). If the deviation card is incorrect by more than 5 °, the plane must not be used for IFR, if I do remember right.
Electric de-icing might cause an additional off-set.
Putting the system in free mode is a good idea in your case and even a legal solution, if placarded at the switch ("slaving u/s, use free mode only").
But since the adjustment is normally not a big deal, the slaving should be fixed.
Electric de-icing might cause an additional off-set.
Putting the system in free mode is a good idea in your case and even a legal solution, if placarded at the switch ("slaving u/s, use free mode only").
But since the adjustment is normally not a big deal, the slaving should be fixed.
