AHRS Red X?

[Bob Ellis]

Although some may think I have posted this in the wrong section please let me explain the issue ...

I have an MGL Voyager G2 EFIS and occasionally I get a red X over the AHRS element of the screen - signifying interrupted data. This is predominantly at my home airfield and initially I put this down to new solar farms built beside the airfield. Then it happened at destination airfields. I discussed with my MGL dealer and tried ferrite rings on the wiring into the EFIS but no joy. He suggested carefully monitoring any electrical inputs near the time of seeing the red X.

I then noticed that the X was happening almost exclusively on the first flight of the day and after selecting an electrical service. I adopted the Bob Nuckolls central point ground (only exception being wing tip landing lights - earthed to outboard rib). With that last bit of information in mind I left the landing lights off for a few flights to discount that as an issue and the red X still appeared.

So if say switching on the fuel pump brings up the X I can make one blip on the pitch trim and it disappears. So it seems making a switch selection can leave "noise" on the electrical system that if loud enough cuts out the AHRS data and ergo the red X.

I wired the aircraft myself but I don't have the electrical knowledge to diagnose this problem and seek advice from the electrical gurus here on the forum.

[Mich48041]

The vast majority of electrical problems are due to bad connections. So check every connection. Do you have a digital copy of an electrical schematic to share with us? If not, there is a free program called ExpressPCB that makes it easy to draw schematics. It is a two part program, one part for the schematic and one part for making a PCB.
Describe the physical location of the MGL wiring in relation to the other aircraft wiring.

[Bob Ellis]

Hi Joe. Thanks for response am away from home but will post diagram soon ... It is from the program you mentioned. Bob

Hi Joe.

The page that has all my SCH drawings is here

The drawings specific to my AHRS are EA (EFIS to CPC Plug) and EB (Inputs to CPC Bulkhead Socket)


The data/ground issue is coming in on pins 11 and 12. For some reason I didn't use shielded wire on the those two - they are separate wires and I thought that this might be the issue so I disconnected EB 11/12 from the terminal strip 03/04 and connected a shielded RCA plug directly from terminal strip 03/04 to the EFIS LAN RCA Plug - this had no effect so I reconnected the aforementioned. I also fitted a ferrite ring on the EFIS to CPC Plug cable but this too had no effect but remains in position.

The plug and socket are here in my KitlogPro entry

Thanks in advance for your help.

Bob