KCS 55A problem

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perossichi
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KCS 55A problem

Post by perossichi »

In slave mode, the heading from the KCS compass system is consistently 10 degrees off to the left, eg Heading on HSI is 300 and compass heading is 310. No erratic behavior just 10 off. In free mode, I can adjust heading to agree with compass.

Strangely, heading on HSI agrees with compass on the ground.

Thoughts anyone?
Sold 2002. Powerflo, Hartzell composite two blade, 530W/430, 345 transponder.
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Rich
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Re: KCS 55A problem

Post by Rich »

I have a similar, though not as severe, behavior:

I swing the compass and HSI against the compass rose. HSI agrees exactly with the CR, mag. compass off a couple of degrees both N-S, but right on target E-W. Therefore agreement between HSI and compass is this same pattern.

But in the air, E-W still looks good, but disparity North approaches 10 degrees, Soth seems to reduce by a couple of degrees. The challenge here is which is wrong (the real question)? There aren't any obvious in-flight ground references around here to check. It's been on my plate to research this some more.

The compass rose is well away from any above-ground metallic structures that I would expect could influence the readings. Maybe some old rebar or pipes or something else under the pavement that affects one differently than the other?
2002 DA40-180: MT, PowerFlow, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210, Orion 600 LED, XeVision, Aspen E5
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Steve
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Re: KCS 55A problem

Post by Steve »

perossichi wrote: Mon Jul 15, 2019 5:05 am In slave mode, the heading from the KCS compass system is consistently 10 degrees off to the left, eg Heading on HSI is 300 and compass heading is 310. No erratic behavior just 10 off. In free mode, I can adjust heading to agree with compass.

Strangely, heading on HSI agrees with compass on the ground.

Thoughts anyone?
While in flight, if you switch from SLAVE to FREE mode for a brief period, then back to SLAVE, does the HSI correct to the compass heading? Mine exhibited this behavior shortly before the KG-102A DG failed. The reason this happens is that the initial SLAVE rate is about 10 times faster than when in SLAVE mode long term. Yours is the same vintage as mine (unless it has already been overhauled) and may be needing overhaul.
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perossichi
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Re: KCS 55A problem

Post by perossichi »

Rich or Steve

Have you tried adjusting the magnetic azimuth detector as outlined in MM 34-28 paragraph 6?

There is also a procedure to adjust slaving control.
Sold 2002. Powerflo, Hartzell composite two blade, 530W/430, 345 transponder.
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