Dear all, my AP failed during my flight home yesterday. The aircraft is a 2008 Mooney Acclaim-S. During the first flight of the day it briefly disengaged twice but I pressed the AP button on the GFC700 control panel and it reengaged and remained stable. During the return flight the AP disconnect alarm triggered without me pressing the red button on the yoke and stayed on until after I had pressed the red AP disconnect button, the AFCS red box warning illuminated on the PFD and the AP refused to reset. I switched the AP on and off a few times in flight using the switch on my instrument panel but it didn't help. I just got the red box on the PFD with AFCS. Fortunately we were in VMC and I hand flew the rest of the journey using the manual pitch trim wheel (old school!) I had previously seen the red box with PTCH appear intermittently a couple of times in January but it was intermittent and seemed to get better by itself. I understand that if the OAT probe fails it can cause this problem but looking at the data on the SD card the OAT was functioning normally. Has anyone else experienced a similar issue, how can I troubleshoot it? Thanks in advance for your advice! Sent from my iPhone using Tapatalk