NCYankee,
I take it you are referring to the ARINC (serial data) roll steering input of the KFC225 (GNSx30/GTNx50 scenario) and not its analog roll steering (KLN94 scenario)?
I never did connect up that analog roll steering... those wires involve access to the back of the TB20 centre stack, which is just too much hassle for the potentially ("potentially", which nobody I know can vouch for first-hand) better turn performance. Plus, there are claims from Honeywell that an extra relay is needed, to invalidate the analog rollsteer signals, when some external mode is active.
With the Sandel EHSI I get an auto-slewing course pointer so already get automatic turns at each waypoint; the only drawback is that the turn is initiated too early.
Peter
Peter,
Yes, I am referring to the ARINC 429 bank angle command to the autopilot. I understand that the KLN94 has an analog roll steering signal that the KFC225 can use, but I don't know how well it works. When DAC was designing their GPSS product they attempted to use the analog KLN94 roll steering signal but found it totally unsatisfactory and gave up. When you upgrade your GPS, you will want to hook up the ARINC 429 interface as it performs great and the auto-slewing is at best a poor substitute as it still uses the CDI deviations in addition to the auto slew OBS to guide the autopilot. Wind correction is as close to immediate as one can get using roll steering, not to mention being able to fly curved courses such as holds and procedure turns which are not defined by the CDI deviations.
OK; that's what I heard too.
I actually don't believe that explanation because the KLN94 outputs ~1 packet per second which, perhaps with some crude interpolation to generate intermediate output values, would do just fine.
I am holding back on the GPS upgrade because the MFD (KMD550) is not fully compatible with any Garmin GPS, so it would become a major refit, of an aircraft which currently does 99.x% of European IFR requirements (noting that LPV is in its infancy here).
