Vans Aircraft Undifferentiated or Other Model
Flight Crew Private
Flight Crew Last 90 Days 19; Flight Crew Total 773; Flight Crew Type 25
Aircraft Equipment Problem Critical
Flight Crew Diverted; Flight Crew Landed in Emergency Condition; Flight Crew Overcame Equipment Problem
Aircraft
I just completed construction of my new vans RV14A. Test flights were completed and more than 40 hours of initial fly off time was completed locally without any issues. I had the plane professionally painted at ZZZ and intended to fly it home to ZZZ1. After my extensive preflight inspection I departed ZZZ and climbed to 6500 feet. Upon level off; I trimmed for cruise flight and engaged the Dynon autopilot which then called for nose up trim; however the trim motor apparently ran away to FULL nose down trim and failed. As soon as the nose dropped below the horizon I quickly disconnected the autopilot but the trim motor stuck at the full nose down position.In spite of full back pressure on the stick; the aircraft was pitched DOWN and I was unable to maintain altitude. I immediately turned toward the nearest GPS airport 19 miles away. My rate of descent left me doubtful that I would make it to the airport and there was only heavily wooded forest beneath me. Fortunately as I neared the treetops; the clearing ahead was the airport boundary and I had to make some extreme low level maneuvers with full power to land on the runway. I had to make a high speed landing but no damage to the aircraft. I was quite certain I was going to DIE that day. Therefore I want to make the aviation community aware of this type of equipment failure.Note: My death grip on the control stick made me unaware that I had keyed the microphone on UNICOM frequency. Other people overheard my comments on radio. The result was that emergency equipment and personnel were standing by and I was really glad to see them. I don't recall ever declaring an emergency.
RV14 pilot reported when he engaged the autopilot in cruise; the trim motor ran away to full nose down trim and failed. He was unable to maintain altitude and landed in that condition with difficulty.