We still have yet to be able to duplicate the problem on the ground. Heck, the problem doesn\'t even occur every flight. It has now flown 4 times in a row with no problems..... I wish I could give you a vivid picture of what is happening, getting a good debrief from the flight crew isn\'t exactly the easiest thing in the world to do. We have started handing the NAV a detailed questionare to describe the problem with troubleshooting procedures. I\'ll keep you posted if I learn more from them....