Government UAS crew reported an engine positioning control issue caused the UAS to enter into an uncontrollable spin. Efforts to control the spin failed and the UAS crashed.

Narrative

During the first flight of the day; the aircraft; a Censys Technologies Sentaero V2 BVLOS; experienced an unknown malfunction after launch; resulting in uncommanded aircraft movement away from the intended route of flight. During this time; the aircraft lost more than 100 feet of altitude before impacting the roadway on the eastern end of the road. No third-party property damage or injuries occurred as a result of the crash. However; the aircraft is damaged beyond the point of economical repair.The crew consisted of five individuals; four of whom have current FAA-issued Remote Pilot Certificates. All checklists were followed using the challenge and response methodology. The flight was programmed to depart from a small grass field off the NW corner of Location A (authorized by a port authority representative) using a VTOL functionality then fly an automated rectangular course south of the road over Location B. Some minor anomalies were noted and addressed during the preflight sequence. Namely motor servo positioning. However; this was later determined to normal behavior. Takeoff initially seemed uneventful; climbing to the expected transition altitude between vertical and horizontal flight. At the top of the climb; the aircraft began to rotate counterclockwise; which at first seemed like normal pre-transition behavior for the aircraft. However; during the third turn; the aircraft began to loose altitude and travel to the Northeast.Aircraft control was transferred to a more experienced remote pilot for the airframe; at which point he attempted to bring the aircraft to a hover; but the aircraft unexpectedly changed to a horizontal flight profile; climbed briefly; and then continued to descend; failing to respond to pilot control inputs. As the aircraft descended; one of the wings made contact with a street light pole; causing a final spin into the ground. At no point during the accident sequence were warning or error indicators present on GCS (Ground Control Station) equipment. All parts of the aircraft were recovered; with the exception of one propeller.Our team will conduct further inspections and investigation to isolate the cause of the malfunction next week.