Dynali H3 EasyFlyer crash near Ontígola, Toledo, Castile-La Mancha, Spain

The ultralight helicopter took off from Ocaña aerodrome on a test flight. Nine minutes later, cruising north at 1,000 feet, the electrical supply failed and the electronically injected engine shut down. The pilot entered autorotation, descending north into wind. On landing the main rotor blades struck the tail mast, detaching the vertical stabiliser, and the aircraft yawed through 180 degrees before stopping. The pilot was unhurt. The investigation found the 250W alternator could not meet peak electrical demand, with an ambient temperature of 32°C contributing to the overload; after nine minutes and twenty seconds the battery fell below 7V and the engine stopped for want of power to the ECU controlling the injectors. The probable cause was given as incorrect execution of the autorotation following the in-flight engine shutdown. Final report ULM A-010/2020.