View Full Version : 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.
Ultranomad
5th Oct 2012, 21:41
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.
A and C
5th Oct 2012, 22:12
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
peterh337
6th Oct 2012, 07:48
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....
Thank you for your responses.
AndiKunzi
7th Oct 2012, 03:06
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.
josam
18th Apr 2014, 12:15
I am grad to reply to any question about KCS55A system, KA51B included.
In fact I have design a tester to check this unit.