Flicked across to the pseudo ILS whilst on the 28 ILS into Blackpool yesterday, and it was giving me half-scale "fly down" deflection whilst established correctly on the real glideslope. Badness!

The most likely explanation for this is that your SkyDemon glideslope was set to a different value (in degrees) than the actual ILS you were tuned to. That, or your GPS altitude was quite different to your actual altitude, which can of course happen (always cross-reference your GPS altitude to your pressure altitude).

Tim I have been dwelling about this for sometime. Simply because it is a very nice, simple and a logical explanation. I must admit that I would have not thought about it. (PS: please don't mention it to the wife though!)

Very Newbytheway

DurhamTeaseAirport

Tim, Having said the above, I do seem to have had the same observations as in the first post here. While the ILS angle and altitude indications were correct, we observed unnecessary 1/3 to 1/2 a scale fly down indication while approaching several airfields.

Also the GS needle seems to appear for a very short time in SD version 2.2 (making its use very limited to non existent) compared to the earlier version in which it did appear to last much longer on approach.

I wonder if others have noticed the same and if there is an explanation/cure.

Very Newbytheway

DurhamTeaseAirport

Or perhaps, since an ILS GS is targetted at the 'aiming point' within the 'touchdown zone' which is around 150-300m in from the end of the runway, if the SD GS is aiming for the actual runway end then it will show a slight 'fly down' deflection in comparison to the aircraft ILS.



Ian

Perhaps so. However I recall it was remarkably accurate in SD's previous version 2.1.1.

Very Newbytheway

DurhamTeaseAirport

We haven't changed it. This is one of those things where our behaviour is very easy to test, using the simulator, from the comfort of your sofa.

That is very useful to know Tim.

Do we know if other users are experiencing the same and if it can be ironed out? I doubt if this is a hardware issue.

Incidentally I note that Newcastle NDB (NT) is not depicted in-line of the runway and currently it appears north of its usual position. I am not sure if the same is true in the CAA maps offered by SD as a second option as I am using SD maps only.

SD remains an excellent product.

Thanks

Very Newbytheway

DurhamTeaseAirport

I haven't heard of anyone else experiencing the issue.

The NT NDB is only drawn offset when its symbol would otherwise conflict with other radio aids or the airfield itself. A line is drawn in the background connecting it to its actual position. The CAA does this offsetting of airfield-based radio navigation aids too.

Thanks Tim for clarifying the displacement of some Navaids on the VFR charts which I must admit I overlooked, when I compared SD VFR charts to my instrument plates (apples & pears). So thanks for the reminder.

So far as the false fly down indication, I do note also the originator of this post had a similar experience to mine. Is there any thing we can do besides ensuring preflight altitude calibration, in order that we could get the correct indication, noting that I was able to obtain a perfect match between the aeroplanes two glide slope indicators and SD's, previously?

Very Newbytheway

DurhamTeaseAirport