EFIS anomaly

[Freo 83]

I have an odd situation with my EFIS range readouts. On my goflight efis and the aircraft MCP efis, the range reads the same distance, but the range on the ND always reads under. That is, if the range on the efis and MCP is say, 40 miles the ND range will read 20 miles and so forth. Any particular reason why this could be ?

 

Cheers.

[scandinavian13 5,192]

 

 

Any particular reason why this could be ?

 

Yeah - whoever wrote your interface did it wrong.

 

When looking at the ND, you will see an arc. At the top of the arc is the current heading/track, etc, which is the "full" distance of whatever you set on the control panel. Half way down the arc (between the top and the 'airplane' at the bottom, is - as one might expect halfway down a scale - half of what your ND setting is. At the bottom of the arc is - naturally - zero.

 

So, if you set 40 on the control panel, the number in the middle of the ND should indicate 20, as it is halfway between the top, and the airplane. 40/2 = 20. If someone coded an interface to display 40 at the mid point, then they need to go back to remediary logic and maths. Setting 40 and seeing 40 at the midpoint means your ND is displaying 80.

[Freo 83]

Thanks for the reply, I dont quite understand your explanation, but what I've done is eliminate the Go Flight efis, and solely used the efis on the MCP.  When I enter a range with the efis switch it still does not correlate to what is shown on the ND. Therefore it has nothing to do with who ever wrote the interface. When I used the FS9 PMDG 737, what ever range I entered on the efis, it showed exactly the same range on the ND.

[scandinavian13 5,192]

Thanks for the reply, I dont quite understand your explanation, but what I've done is eliminate the Go Flight efis, and solely used the efis on the MCP.  When I enter a range with the efis switch it still does not correlate to what is shown on the ND. Therefore it has nothing to do with who ever wrote the interface. When I used the FS9 PMDG 737, what ever range I entered on the efis, it showed exactly the same range on the ND.

 

Explain, please. "It showed exactly the same range on the ND" isn't actually telling me much. I need to know how you are determining something is wrong here.

 

The common misconception is that the number that you dial on the EFIS control panel is the number that will show on the ND. This is not true.

 

Example: I dial in 40 on the EFIS Control Panel. The EFIS will show:

 

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20

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^

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...because that 20 is at the mid point of the display.

 

 

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/\ ------40

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20

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^ ------ 0

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[Freo 83]

Hi Kyle,  I now understand what you are getting at. All I meant was, that when I input a range figure via the Efis control knob, say, 40, what you actually saw on the ND was the figure 20 (in white). I naturally presumed that it should have read 40, as this was the case in my FS9 737. but its not that now in the NGX.

 

Cheers.