UAV - Unpiloted Aerial Vehicle
Flight Crew Commercial; Flight Crew Instrument
Flight Crew Last 90 Days 3; Flight Crew Total 779; Flight Crew Type 2
Aircraft Equipment Problem Critical; Ground Event / Encounter Ground Strike - Aircraft; Inflight Event / Encounter Loss Of Aircraft Control
Aircraft Aircraft Damaged
Aircraft
The V-10ET Unmanned Aircraft System had just completed getting some minor upgrades to the tail rotor system with a new motor to replace an older motor that had a bearing fail. On top of that it was running new code that changed how lost comms got handled so that we would not land on top of a payload carried in sling load. We had run the code in the simulator and with the tweaks; we were happy with the performance. We did a ground run of the helicopter to cycle the new batteries that we had purchased and to exercise the tail motor; which yielded nominal change in the performance. I flew the V-10ET starting with just a normal return to service flight with maneuvering in fully stable and mission mode to run our lost comms plan to validate if it did execute the maneuver as planned. The landing plan in mission mode seemed rather aggressive but not out of control. We wanted to try it again but closer; so we flew the landing plan right in front of us. The Helicopter seemed less aggressive but when arriving at the second waypoint in the plan we experienced a loss of main rotor RPM with the piccolo flight control system commanding full up pitch collective; effectively stopping the main rotor blades. With the altitude we had and almost zero forward airspeed; an autorotation was not possible from a pilot override. Post-crash inspection showed only damage to the side frames of the helicopter; main rotor; tail rotor and swash arms. The repair cost was under 500 dollars for the items that needed repair or replacement.Our internal investigation revealed we had a connector failure due to the new batteries being able to provide more current when needed then our old set of batteries. This caused the main flight battery connector to heat up and melt when the current draw increased beyond what the connectors where rated for. It was a combination of new batteries; new software that was more aggressive; and connectors that where sub-par for what was needed with the new software.
UAV Operator reported loss of aircraft control resulting in ground impact with some damage to the UAV.