What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Tail rotor contacted power cable while installing cable. Caused dynamic rollover. Fell to ground. (.4)witnesses reported that the helicopter had just released from positioning a fiber optic cable on top of a power pole. An external line is hung over the left landing skid, forward of the front leg, and a shoe is used to cradle the cable to lift and position it in place for permanent attachment. A lineman was on the pole and in the process of permanently attaching the cable to the pole when the pilot maneuvered the helicopter away and behind the lineman about five feet. Another lineman was standing on the left side landing skid and was then going to install vibration dampers on the cable. The lineman on the pole stated that everything was normal when he heard what sounded like a clicking sound or a sound like a card in a spoked wheel. The lineman on the pole stated that he knew that the helicopter was in the wires and saw pieces of the helicopter flying. The lineman ducked down on the pole, and when he looked up again, the helicopter had already gone through the transmission wires and was laying on its right side on the ground. Impact signautres of a cable strike were found on both tailrotor blades. The cable that the helicopter was positioned next to was severed. Further inspection of the severed cable noted that 19 of the 22 strands that make up the fiber optic cable received varying amounts of mechanical damage prior to failure. During the post-crash wreckage documentation and inspection, no evidence was found to indicate a mechanical failure or malfunction. (-23) the helicopter was being operated under FAR 133 while installing fiberoptic cables on power transmission structures. Evidence suggests the aircraft tail rotor contacted the main power transmission cables. At this point, the helicopter experienced a dynamic rollover into other suspended cables before impacting the terrain below. The operation required 3 people; a lineman on the structure, an individual standing on the l/h helicopter skid, and the pilot, operating the aircraft from the left seat.
As the FAA filed it
TAIL ROTOR CONTACTED POWER CABLE WHILE INSTALLING CABLE. CAUSED DYNAMIC ROLLOVER. FELL TO GROUND. (.4)WITNESSES REPORTED THAT THE HELICOPTER HAD JUST RELEASED FROM POSITIONING A FIBER OPTIC CABLE ON TOP OF A POWER POLE. AN EXTERNAL LINE IS HUNG OVER THE LEFT LANDING SKID, FORWARD OF THE FRONT LEG, AND A SHOE IS USED TO CRADLE THE CABLE TO LIFT AND POSITION IT IN PLACE FOR PERMANENT ATTACHMENT. A LINEMAN WAS ON THE POLE AND IN THE PROCESS OF PERMANENTLY ATTACHING THE CABLE TO THE POLE WHEN THE PILOT MANEUVERED THE HELICOPTER AWAY AND BEHIND THE LINEMAN ABOUT FIVE FEET. ANOTHER LINEMAN WAS STANDING ON THE LEFT SIDE LANDING SKID AND WAS THEN GOING TO INSTALL VIBRATION DAMPERS ON THE CABLE. THE LINEMAN ON THE POLE STATED THAT EVERYTHING WAS NORMAL WHEN HE HEARD WHAT SOUNDED LIKE A CLICKING SOUND OR A SOUND LIKE A CARD IN A SPOKED WHEEL. THE LINEMAN ON THE POLE STATED THAT HE KNEW THAT THE HELICOPTER WAS IN THE WIRES AND SAW PIECES OF THE HELICOPTER FLYING. THE LINEMAN DUCKED DOWN ON THE POLE, AND WHEN HE LOOKED UP AGAIN, THE HELICOPTER HAD ALREADY GONE THROUGH THE TRANSMISSION WIRES AND WAS LAYING ON ITS RIGHT SIDE ON THE GROUND. IMPACT SIGNAUTRES OF A CABLE STRIKE WERE FOUND ON BOTH TAILROTOR BLADES. THE CABLE THAT THE HELICOPTER WAS POSITIONED NEXT TO WAS SEVERED. FURTHER INSPECTION OF THE SEVERED CABLE NOTED THAT 19 OF THE 22 STRANDS THAT MAKE UP THE FIBER OPTIC CABLE RECEIVED VARYING AMOUNTS OF MECHANICAL DAMAGE PRIOR TO FAILURE. DURING THE POST-CRASH WRECKAGE DOCUMENTATION AND INSPECTION, NO EVIDENCE WAS FOUND TO INDICATE A MECHANICAL FAILURE OR MALFUNCTION. (-23) THE HELICOPTER WAS BEING OPERATED UNDER FAR 133 WHILE INSTALLING FIBEROPTIC CABLES ON POWER TRANSMISSION STRUCTURES. EVIDENCE SUGGESTS THE AIRCRAFT TAIL ROTOR CONTACTED THE MAIN POWER TRANSMISSION CABLES. AT THIS POINT, THE HELICOPTER EXPERIENCED A DYNAMIC ROLLOVER INTO OTHER SUSPENDED CABLES BEFORE IMPACTING THE TERRAIN BELOW. THE OPERATION REQUIRED 3 PEOPLE; A LINEMAN ON THE STRUCTURE, AN INDIVIDUAL STANDING ON THE L/H HELICOPTER SKID, AND THE PILOT, OPERATING THE AIRCRAFT FROM THE LEFT SEAT.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.