Written by Dan Magnus, Avionics Tech Rep
Honeywell's GNS-XLS is a Flight Management System that provides control for an aircraft's navigation sensors, computer-based flight planning, fuel management and frequency management, among many other necessary capabilities. When this unit begins to malfunction, it is critical to get it back on line quickly.
I recently fielded a phone call from a DOM asking for troubleshooting advice when the screen on the GNS-XLS went white. Here are the steps I used to determine the cause and provide the solution.
The best way to determine if a unit is faulty is to install another and see if the squawk disappears. I sent out a loaner to arrive the next day. After the unit was installed, the screen remained white, telling me it wasn't the unit causing the squawk.
Next, I had him unhook the antenna. This immediately brought the screen back to its normal state. We replaced the antenna and the system is back on-line.
If you need help troubleshooting or repairing your avionics, contact Avionics Tech Support.