What happened
A certified flight instructor and a prospective student were conducting a short demonstration flight in clear VFR conditions. Approximately three minutes after departing from the airport, the helicopter was flying over an urban park area located about 1.5 miles west of the departure airfield.
During the flight, witnesses reported hearing noises described as popping, banging, and thumping. Following these sounds, the engine ceased running. The main rotor then departed its normal plane of rotation. The rotor maintained sufficient RPM to strike the right front portion of the cockpit windshield and hit the passenger seated on the right side. Following this contact, the main rotor RPM decayed immediately and stopped. The aircraft was observed in a steep, nose-down angle of descent until it impacted the ground.
No fatalities were reported in the provided text, though the passenger was struck by the rotor.