What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Heard to throttle back level flight tail rose. Struck by main rotor. Fell to ground. Typical of abrupt cylic use. (.4)the homebuilt mini 500 helicopter was in level flight about 900 to 1200 feet, when the engine sounds stopped. The helicopter's nose dropped, and one main rotor blade struck the tailboom and separated from the rotor head. The helicopter descended and struck the ground 90 degrees nose down. Examination of the non-certificated 2 cycle Rotax engine did not reveal a reason for the power loss. The engine manufacturer published the maximum continuous RPM as 6,500. Other builders reported that when the helicopter's rotor RPM was operated at the top of the green arc, the engine operated about 6,700 RPM. The NTSB database revealed 23 mini-500 accidents in 1997 and 1998. Twelve of those involved a loss of engine power. The Rotax operator's manual stated, '...this engine by design is subject to sudden stoppage...never fly the aircraft equipped with this engine at locations, airspeeds, altitudes...from which a successful no-power landing cannot be made...' (-23) witnesses observed the aircraft in straight and level flight. Severa l witnesses reported they heard the engine noise go away indicating a loss of power for unknown reasons. The witnesses further stated that they observed the tailboom go into the main rotor, and one of the rotorblades depart the aircraft. The aircraft then moved erratically for a short time. The aircraft then pitched down 100 degrees and impacted the ground in that attitude. The pilot, who was the sole occupant, was fatally injured in the accident.
As the FAA filed it
HEARD TO THROTTLE BACK LEVEL FLIGHT TAIL ROSE. STRUCK BY MAIN ROTOR. FELL TO GROUND. TYPICAL OF ABRUPT CYLIC USE. (.4)THE HOMEBUILT MINI 500 HELICOPTER WAS IN LEVEL FLIGHT ABOUT 900 TO 1200 FEET, WHEN THE ENGINE SOUNDS STOPPED. THE HELICOPTER'S NOSE DROPPED, AND ONE MAIN ROTOR BLADE STRUCK THE TAILBOOM AND SEPARATED FROM THE ROTOR HEAD. THE HELICOPTER DESCENDED AND STRUCK THE GROUND 90 DEGREES NOSE DOWN. EXAMINATION OF THE NON-CERTIFICATED 2 CYCLE ROTAX ENGINE DID NOT REVEAL A REASON FOR THE POWER LOSS. THE ENGINE MANUFACTURER PUBLISHED THE MAXIMUM CONTINUOUS RPM AS 6,500. OTHER BUILDERS REPORTED THAT WHEN THE HELICOPTER'S ROTOR RPM WAS OPERATED AT THE TOP OF THE GREEN ARC, THE ENGINE OPERATED ABOUT 6,700 RPM. THE NTSB DATABASE REVEALED 23 MINI-500 ACCIDENTS IN 1997 AND 1998. TWELVE OF THOSE INVOLVED A LOSS OF ENGINE POWER. THE ROTAX OPERATOR'S MANUAL STATED, '...THIS ENGINE BY DESIGN IS SUBJECT TO SUDDEN STOPPAGE...NEVER FLY THE AIRCRAFT EQUIPPED WITH THIS ENGINE AT LOCATIONS, AIRSPEEDS, ALTITUDES...FROM WHICH A SUCCESSFUL NO-POWER LANDING CANNOT BE MADE...' (-23) WITNESSES OBSERVED THE AIRCRAFT IN STRAIGHT AND LEVEL FLIGHT. SEVERA L WITNESSES REPORTED THEY HEARD THE ENGINE NOISE GO AWAY INDICATING A LOSS OF POWER FOR UNKNOWN REASONS. THE WITNESSES FURTHER STATED THAT THEY OBSERVED THE TAILBOOM GO INTO THE MAIN ROTOR, AND ONE OF THE ROTORBLADES DEPART THE AIRCRAFT. THE AIRCRAFT THEN MOVED ERRATICALLY FOR A SHORT TIME. THE AIRCRAFT THEN PITCHED DOWN 100 DEGREES AND IMPACTED THE GROUND IN THAT ATTITUDE. THE PILOT, WHO WAS THE SOLE OCCUPANT, WAS FATALLY INJURED IN THE ACCIDENT.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.