ILS EHSI shows wrong data

[discordia]

greetings everybody!

I will post my question here as i really cant imagine that i have found a bug which is not known already. On the other hand, i also was not able to find this to be described somewhere else. Maybe i just do something wrong all the time?

Occasionally i get a strange issue when doing an approach with the IXEG. Please look at both EHIS on the first screenshot. Looking at the FO's EHIS and comparing it with the one from the pilots side, you can clearly see how they completely mismatch. I can only fix that by clicking  "Tune NAV 1/2" from inside xplanes default map after selecting the desired runway. As you can see on the second screenshot it looks fine again after doing so. 

This is not happening always, but it happened enough times now that i need to always double-check.

[mmerelles]

Hi Discordia

 

On the first picture:

I am unsure being understanding properly what you are trying to point out. The big difference on the information being displayed is capt. side being set to ILS/VOR mode and aligned to course 180 as per the MCP left dial (this is a pilot error miss configuration you are landing RWY23L as per the FMC so magnetic course must be around 230 (+/- 5), while the f/o side is set on the pedestal to MAP mode thus showing the magenta and aligned to the aircraft flying direction.

I do not see anything wrong here except pilot in command did not set left course properly on the mcp showing 180 instead of proper ILS mag course

 

On the second picture:

Everything looks the same except you have set capt. left mcp course to 228 thus the display is re-aligned to this course but the display mode still shows VOR/ILS mode while the f/o side is still set to MAP mode and still aligned to aircraft flying direction as per the magenta.

 

Does this cover your doubt? or can you elaborate a bit more something i may have overlooked

[discordia]

thank you for the quick answer mmerelles,

yes, you are absolutely right on the MCP configuration. When doing my approach i usually set COURSE  and HDG to what is written in the FMC's APPOACH REF Page (also for FO). But indeed, at the point i took the first screenshot its wrongly set to 180, on the second screenshot it is then correctly on 228 (apparently because of clicking  "Tune NAV 1/2" from inside xplanes default map).

I think the real issue i was seeing in some flights was, when i first switch CPT EHSI to VOR/ILS Mode, and afterwards set the MCP, that then then EHSI does not update and still shows the course that was set on the MCP before i initially switched to ILS/VOR Mode.

Currently i am not at home, i will re-try later and give more emphasize on this, maybe i do it unconsciously at different timings, thus why it does not happen always.

 

[Litjan]

Hi discordia,

Not sure what to say - of course your screens show totally different pictures - one is set to the "EXPANDED VOR/ILS" mode, one is showing the "EXPANDED MAP" - two totally different selections.

The VOR/ILS mode will only show a compass rose (or a section of it), with a deviation bar centered along the CRS set on the onside MCP course selector. The MAP will show the waypoints as programmed into the FMS - along with a LOC and GS deviation bar if a valid ILS frequency is set on the onside VHF radio.

They will somewhat "look" the same if the COURSE set for the EXPANDED ROSE mode matches the string of waypoints on your final approach - they will be "parallel" - but conceptually those two modes are completely different.

Cheers, Jan

 

Edited November 15, 2017 by Litjan

[discordia]

ok false alarm, i think it was just a corner case and i cant reproduce it anymore .. Its difficult to explain what i meant before so sorry for all the confusion. I am aware that both, captains and fo's EHSI are showing completely different things. I just thought this will help to explain it better.

Let me try to explain it different ... on the first screenshot you see 180 COURSE, when i tune the dial manually to 228 i would expect to see what i can see on the second screenshot's captains EHSI, but the screen did not change and the "course needle" is not moving. After using the map tune method it actually changed and looked like in screenshot 2. Basically the issue was, that -during ILS/VOR mode- if i changed the COURSE dial, the needle was not moving "in real time" at all. Now i did 4 landings and was not able to reproduce it and all works fine. I will monitor this on some longer hops and let you know ... Hope i was able to explain it better now.

BTW... Jan, IXEG Team ... i really love this AC, good job ...

 

**UPDATE**

Ok forget about the text, i did a quick video ... So this "needle movement" did not work for some few approaches that were done in IVAO after >1 hour hops. Walkaround was to use the "map tune" method.

 

Edited November 15, 2017 by discordia

[Litjan]

Hi discordia,

ah, now I get what you were seeing - but this is the first time I ever heard that. Keep an eye out for it - maybe it is a fringe case that you can reproduce, and then we can take a look at it!

Thanks for the nice words and let us know if anything else comes up!

Cheers, Jan