Sometimes the ARINC 429 channel from the #1 Garmin 430 to the Sandel doesn’t work. The symptom is that the Sandel can’t display the moving map, the glide slope indication, or the CDI.
Sandel has seen this problem before and doesn’t know what causes it yet.
If this has happened to you, please let me know so we can pool our knowledge of the problem.
I think I have found that if I turn the avionics master on soon enough after the HSI is turned on (which is when the masters on turned on), that the problem does not happen.
Also, I found that the problem never happens if the Sandel is in maintenance mode. However, I am reluctant to fly around with the Sandel in this mode. But that I can always make it work this way suggests a software bug.
Sandel also thinks it is a software bug, but they don’t know if the problem is with the Garmin or the Sandel.