What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
On December 24, 2018, an Airbus industries BK145EC registration N145EC operated by the mayo clinic a part 135 operator flew from eau claire WI, (keau) to Strum, WI landing approximately 22:15. The aircraft was flying a part 91 repositioning flight with the pilot and two crewmembers onboard. The flight had a VFR (visual flight rules) flight plan filed and the crew were wearing night vision goggles (NVG). The pilot stated the weather was clear with 10-mile visibility, winds 5@350 degrees. Prior to the approach, the pilot briefed on an optional alternate landing zone. The pilot surveyed the landing zone and started a shallow approach. The pilot stated, ?about five minutes before landing on scene at the Strum Wisconsin fire department, the crew hailed the lz coordinator on marc 2 frequency. The brief given talked about the fire trucks blocking the north and south sides of the lz and confirmed that there were no overhead obstructions. The pilot noted the light pollution from the fire trucks and sheriff vehicles made visibility difficult?.
The pilot stated, ?on approach to the Strum Wisconsin fire department, the crew was calling out obstacles: trees, fire trucks, flag poles. At about 30? AGL, I noticed that there was a street sign on a pole on the corner of the intersection where I planned on terminating my approach. Once I noticed the street sign, I decelerated forward movement and thus, dipped the tail a few feet. This is when the tail rotor contacted the hose rack on top of the fire truck. After feeling the bump of the tail rotor contacting the fire truck, I immediately felt a vibration in the pedals and the aircraft started spinning. I instinctively put in pedal to oppose the spin and then lowered the collective to reduce torque on the airframe. I believe the aircraft spun about 180 degrees to the right before landing, facing south. I immediately rolled the throttles to idle to stop the sliding. I think we slid about 30 degrees while in contact with the ground before coming to rest facing southwest. After checking with my crew on ics to see if everyone was ok, I rolled the throttles to off. We immediately checked the scene to see if any of the ground personnel were injured. While checking on the ground crew, I called our flight tracking center and notified them of the incident and zero injuries." The helicopter suffered damage to the tail rotor blades, and subsequent ground impact spreading the skids.
As the FAA filed it
ON DECEMBER 24, 2018, AN AIRBUS INDUSTRIES BK145EC REGISTRATION N145EC OPERATED BY THE MAYO CLINIC A PART 135 OPERATOR FLEW FROM EAU CLAIRE WI, (KEAU) TO STRUM, WI LANDING APPROXIMATELY 22:15. THE AIRCRAFT WAS FLYING A PART 91 REPOSITIONING FLIGHT WITH THE PILOT AND TWO CREWMEMBERS ONBOARD. THE FLIGHT HAD A VFR (VISUAL FLIGHT RULES) FLIGHT PLAN FILED AND THE CREW WERE WEARING NIGHT VISION GOGGLES (NVG). THE PILOT STATED THE WEATHER WAS CLEAR WITH 10-MILE VISIBILITY, WINDS 5@350 DEGREES. PRIOR TO THE APPROACH, THE PILOT BRIEFED ON AN OPTIONAL ALTERNATE LANDING ZONE. THE PILOT SURVEYED THE LANDING ZONE AND STARTED A SHALLOW APPROACH. THE PILOT STATED, ?ABOUT FIVE MINUTES BEFORE LANDING ON SCENE AT THE STRUM WISCONSIN FIRE DEPARTMENT, THE CREW HAILED THE LZ COORDINATOR ON MARC 2 FREQUENCY. THE BRIEF GIVEN TALKED ABOUT THE FIRE TRUCKS BLOCKING THE NORTH AND SOUTH SIDES OF THE LZ AND CONFIRMED THAT THERE WERE NO OVERHEAD OBSTRUCTIONS. THE PILOT NOTED THE LIGHT POLLUTION FROM THE FIRE TRUCKS AND SHERIFF VEHICLES MADE VISIBILITY DIFFICULT?.
THE PILOT STATED, ?ON APPROACH TO THE STRUM WISCONSIN FIRE DEPARTMENT, THE CREW WAS CALLING OUT OBSTACLES: TREES, FIRE TRUCKS, FLAG POLES. AT ABOUT 30? AGL, I NOTICED THAT THERE WAS A STREET SIGN ON A POLE ON THE CORNER OF THE INTERSECTION WHERE I PLANNED ON TERMINATING MY APPROACH. ONCE I NOTICED THE STREET SIGN, I DECELERATED FORWARD MOVEMENT AND THUS, DIPPED THE TAIL A FEW FEET. THIS IS WHEN THE TAIL ROTOR CONTACTED THE HOSE RACK ON TOP OF THE FIRE TRUCK. AFTER FEELING THE BUMP OF THE TAIL ROTOR CONTACTING THE FIRE TRUCK, I IMMEDIATELY FELT A VIBRATION IN THE PEDALS AND THE AIRCRAFT STARTED SPINNING. I INSTINCTIVELY PUT IN PEDAL TO OPPOSE THE SPIN AND THEN LOWERED THE COLLECTIVE TO REDUCE TORQUE ON THE AIRFRAME. I BELIEVE THE AIRCRAFT SPUN ABOUT 180 DEGREES TO THE RIGHT BEFORE LANDING, FACING SOUTH. I IMMEDIATELY ROLLED THE THROTTLES TO IDLE TO STOP THE SLIDING. I THINK WE SLID ABOUT 30 DEGREES WHILE IN CONTACT WITH THE GROUND BEFORE COMING TO REST FACING SOUTHWEST. AFTER CHECKING WITH MY CREW ON ICS TO SEE IF EVERYONE WAS OK, I ROLLED THE THROTTLES TO OFF. WE IMMEDIATELY CHECKED THE SCENE TO SEE IF ANY OF THE GROUND PERSONNEL WERE INJURED. WHILE CHECKING ON THE GROUND CREW, I CALLED OUR FLIGHT TRACKING CENTER AND NOTIFIED THEM OF THE INCIDENT AND ZERO INJURIES." THE HELICOPTER SUFFERED DAMAGE TO THE TAIL ROTOR BLADES, AND SUBSEQUENT GROUND IMPACT SPREADING THE SKIDS.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.