What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) When flying a passenger and cargo to a remote landing area the pilot manuevered his heli. To land within 10 feet of a seismic survey electronic junction box. While still at a hover, an unsecured large canvas bag (normally secured underneath the electronic junction box) was caught by the rotor wash and blew into the main rotor system. Pilot and passenger both reported that the heli. Then had a severe vibration until the rotor system separated from the a/c and the rest of the heli. Fell to the ground upright. On-scene investigation shows the upper half of the main rotor mast housing, the entire main rotor mast, main rotor hub, and main rotor blades departed the a/c as a sinle unit. The pilot estimates the main rotor system separated while he was still at a skid height of 1 to 2 feet. There was no fire, no injuries, and very little other apparent damage to heli. The operator's director of maintenance was at the accident scene and said that the skid gear on the heli. Did not show signs of a hard landing. (.4)the helicopter was transporting a passenger to a remote site to change the batteries on a seismic recorder box. As the pilot terminated the landing approach to a hover at a skid height of 1 to 2 feet above the ground, an empty canvas heli-bag that was lying on the ground blew into the helicopter's main rotor system. The helicopter developed 'a severe' vibration, the main rotor system separated, and the helicopter impacted the ground in a 'moderately hard landing.' The operator stated that the accident could have been prevented by 'making sure that heli-bag is secure and that aircraft is a safe distance from bag and box.'
As the FAA filed it
(-23) WHEN FLYING A PASSENGER AND CARGO TO A REMOTE LANDING AREA THE PILOT MANUEVERED HIS HELI.TO LAND WITHIN 10 FEET OF A SEISMIC SURVEY ELECTRONIC JUNCTION BOX. WHILE STILL AT A HOVER, AN UNSECURED LARGE CANVAS BAG (NORMALLY SECURED UNDERNEATH THE ELECTRONIC JUNCTION BOX) WAS CAUGHT BY THE ROTOR WASH AND BLEW INTO THE MAIN ROTOR SYSTEM. PILOT AND PASSENGER BOTH REPORTED THAT THE HELI.THEN HAD A SEVERE VIBRATION UNTIL THE ROTOR SYSTEM SEPARATED FROM THE A/C AND THE REST OF THE HELI.FELL TO THE GROUND UPRIGHT. ON-SCENE INVESTIGATION SHOWS THE UPPER HALF OF THE MAIN ROTOR MAST HOUSING, THE ENTIRE MAIN ROTOR MAST, MAIN ROTOR HUB, AND MAIN ROTOR BLADES DEPARTED THE A/C AS A SINLE UNIT. THE PILOT ESTIMATES THE MAIN ROTOR SYSTEM SEPARATED WHILE HE WAS STILL AT A SKID HEIGHT OF 1 TO 2 FEET. THERE WAS NO FIRE, NO INJURIES, AND VERY LITTLE OTHER APPARENT DAMAGE TO HELI. THE OPERATOR'S DIRECTOR OF MAINTENANCE WAS AT THE ACCIDENT SCENE AND SAID THAT THE SKID GEAR ON THE HELI.DID NOT SHOW SIGNS OF A HARD LANDING. (.4)THE HELICOPTER WAS TRANSPORTING A PASSENGER TO A REMOTE SITE TO CHANGE THE BATTERIES ON A SEISMIC RECORDER BOX. AS THE PILOT TERMINATED THE LANDING APPROACH TO A HOVER AT A SKID HEIGHT OF 1 TO 2 FEET ABOVE THE GROUND, AN EMPTY CANVAS HELI-BAG THAT WAS LYING ON THE GROUND BLEW INTO THE HELICOPTER'S MAIN ROTOR SYSTEM. THE HELICOPTER DEVELOPED 'A SEVERE' VIBRATION, THE MAIN ROTOR SYSTEM SEPARATED, AND THE HELICOPTER IMPACTED THE GROUND IN A 'MODERATELY HARD LANDING.' THE OPERATOR STATED THAT THE ACCIDENT COULD HAVE BEEN PREVENTED BY 'MAKING SURE THAT HELI-BAG IS SECURE AND THAT AIRCRAFT IS A SAFE DISTANCE FROM BAG AND BOX.'
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.