TBM 700/TBM 850
Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 16; Flight Crew Total 1012; Flight Crew Type 700
Workload
Aircraft Equipment Problem Less Severe; Deviation - Altitude Excursion From Assigned Altitude; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Flight Crew Returned To Clearance
Weather; Human Factors; Aircraft
I started the TBM8 and there was a failure of the Automated Flight Control System (AFCS). I recycled the avionics power; but it did not correct the problem. I decided to take off for MEV despite no automated control (i.e. no autopilot) thinking that I can just hand fly the machine. I have been repeatedly taught how to hand fly the machine if the automation fails. That decision to takeoff was a mistake; because a failure of the AFCS also causes a loss of trim motor control. That makes it very difficult to keep the machine in coordinated flight.I reported to ATC enroute that I was having difficulty controlling the altitude and course due to an avionics failure (I was working hard to control the aircraft in the face of the winter storm entering the region); and I was ultimately cleared for the GPS Approach into MEV from the IAF. It was real IMC over the High Sierras at that point; and I proceeded to the next fix. It was very difficult to hand fly the aircraft due to moderate to severe turbulence which I had heard reported previously by another pilot. I was not on course; struggling to maintain the course and proper altitude and at all times trying to keep wings level. I have never been in a truly severe turbulence condition; and there is a reason why you need an autopilot for single pilot IFR. I broke out of the clouds and turbulence; but substantially off course; but I was safe and clear of the mountains. I told NORCAL that I was clear of the clouds and had the airport in sight. At that point I cancelled my IFR flight plan. I landed safely at MEV.This was a difficult lesson. I will never again fly single pilot IFR without the automated control systems properly operational. I should have shut the machine down at [departure airport] and resolved the problem prior to taking off. A lesson learned to be sure.
TBM8 pilot reported struggling to maintain altitude and track after departing with the Automated Flight Control System (AFCS) inoperative.