G1000 instrument intermittent red X’s on EIS

[Schllc]

So I have this problem where intermittently I lose most of my engine monitoring items. 
The avionics shop says it’s an AP issue and the AP says I need to bring to an avionics shop. 
Has anyone experienced this before?

I have pulled the plugs and reseated all of them with no improvement  

[Danb]

Ray most likely the GEA 71 unit I believe it relays the parameters to the display. I’d try to pull it out and rerack it see what happens.

D

[Schllc]

7 minutes ago, Danb said:

Ray most likely the GEA 71 unit I believe it relays the parameters to the display. I’d try to pull it out and rerack it see what happens.

D

I’ve done that, and there is some history of this in the logs, and it’s even been replaced once. 
 

[Danb]

Don’t know the replacement costs with our LRUs it’s a quick fix hopefully 

[Ragsf15e]

1 hour ago, Schllc said:

So I have this problem where intermittently I lose most of my engine monitoring items. 
The avionics shop says it’s an AP issue and the AP says I need to bring to an avionics shop. 
Has anyone experienced this before?

I have pulled the plugs and reseated all of them with no improvement  

This is a long shot, but it’s not happening around the time you’ve uploaded new monthly navdata is it? I have that happen on the Meridian I fly when the pfd and mfd haven’t successfully started and restarted the same number of times to check the data before using it.  Remember it says “new data will be verified before use.”?  My recourse is shutting off all electrical power and starting back up which fixes it.  I have no idea why mismatched data Xs the engine instruments but it does.

[Schllc]

1 hour ago, Danb said:

Don’t know the replacement costs with our LRUs it’s a quick fix hopefully 

Yeah, even the main display is only a flat of 2500.  If it’s an LRU that would be the easiest fix, I suspect it isn’t that given the logbook history. 
The challenge if no one locally wants to help, I’m not sure how to get it somewhere else.  
it’s going to take someone patient and thorough, not something very common in thr modern world…

speaking of that and for the sake of levity, I saw this today and laughed. 

 

[Schllc]

28 minutes ago, Ragsf15e said:

This is a long shot, but it’s not happening around the time you’ve uploaded new monthly navdata is it? I have that happen on the Meridian I fly when the pfd and mfd haven’t successfully started and restarted the same number of times to check the data before using it.  Remember it says “new data will be verified before use.”?  My recourse is shutting off all electrical power and starting back up which fixes it.  I have no idea why mismatched data Xs the engine instruments but it does.

It did not occur during an update, but I am due one.  
that’s easy enough to check, I should be so lucky…

[Ragsf15e]

11 minutes ago, Schllc said:

It did not occur during an update, but I am due one.  
that’s easy enough to check, I should be so lucky…

Yeah I doubt it as well, but I’ve had it happen even several days after an update where I put in the stby navdata, then on the switchover day, boom, I’m telling ground that ill be off the radio for two minutes for a reboot.

[MatthiasArnold]

To me it‘s a little bit confusing, that the problem only applies to a subset of the sensors connected to the GEA. There is no obvious pattern at first glance (e.g., all pressure sensors fail which could hint to checking the sensor supply voltages provided by the GEA). 

During the course of this year I had some trouble with the configuration data of the GEA which could be fixed by reprogramming the GEA only plus reloading the GEA specific configuration plus saving it to the configuration module.

When following this avenue make sure to select the correct configuration options (e.g. Kulite vs .. pressure senosors, ..). Don’t ask me how I know…

Not an avionics specialist, just ordinary electrical engineer.

Best, 

Matthias

[philiplane]

The MP/FF/RPM engine indications go through plugs on the aft baffle and are notorious for losing contact after flying in rain. Corrosion sets into the contacts. The oil pressure sensor may also have the same style three pin molex connector, and on that side of the engine this can get baked by the heat of the turbo. The corrosion problem however usually only takes out one circuit at a time.

Those four circuits all operate the same way, so if there is a chafed power wire on one of those circuits it can take out the power supply inside the GEA71. Which will take out every circuit that uses 5V power to the sensor. It would not affect the EGT/CHT/TIT circuits. You will want to follow the wires from each sensor, back to the firewall. My guess is that somewhere on one of those wires, there is chafing and a short to ground. Some of these are wrapped in a corrugated protector, which ironically can chew into the wires too. Especially the MP sensor wires because they pass over the cylinders and the extra heat degrades the plastic. 

I would examine those engine sensor wires first. I don't have the airframe manual open so I can't give any recommendations on the trim sensors or the BAT2 readings. 

There is also the problem of the GEA71 and GDU connectors. I have found plenty of unlocked pins in the connectors. So they look fine, but when mated to the socket, the pin will push back into the connector, giving a poor connection. You have to take a 1/16" diameter, four inch long pin with a flat end, or a T3 or T5 Torx screwdriver which has the small flat end you need, and push in on each of the pins to make sure they are locked. You might also find bent pins on the GDU connector if there was recently maintenance done and they weren't careful to put the plug straight onto the back of the GDU. This damage would result in loss of a complete data line though, or loss of a dimmer circuit, etc. Not a partial failure. 

Edited November 19, 2023 by philiplane

[Schllc]

Philip,

that was extremely informative and I hope I do not have to go that route. 
per garmins instructions, we reloaded the software to confirm the gea 71.. 
they said after that didn’t work that the readings I was still getting were all passive, egt,cht, fuel quantity and oil pressure, they believe the power supply to have gone bad and today we did an exchange and will reload and see if that solves the problem. 
chasing out all,of those wires will be a black hole of time…

fingers crossed!

[Schllc]

Thanks for the help from everyone, private messages as well.  
Turns out it was the gea71. 
Installed software loaded and all back to normal!

Guess I don’t have to throw the g1000 plane away yet. 

[William Munney]

Modern glass cockpits.  Sheeeeesh