What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
2021-02-13, N352LL, lifelinkiii augusta, helicopter took off from Alexandria, MN (kaxn) airport and hit an object with one rotor blade.
After transitioning straight ahead to forward flight on rwy 31, the PIC made a left climbing turn as destination was southbound. At an altitude between 300-400 ft , along the southern boundary of the airfield, the PIC heard a single noise, and stated he may have felt a minor control movement. He rolled out and asked the medical crew in back if something had fallen on the floor? The answer was no.
The PIC immediately turned left and was in position for a left downwind. He returned, had a panel check conducted and then shutdown the aircraft. Walkaround inspection showed a leading edge rotor blade impact. The impact was approximately 60 inches from the attach point on the hub. The impact was about 1/2 inch wide and 1/2 inch deep. 6 inches aft of the leading edge impact was a hole about 1 inch that penetrated the bottom of the blade and exited the top, through the honey comb and composite material. Composite material had started to peel away at a 45 degree angle.
It was unclear what the impact could have been. Nobody on board the aircraft had seen anything. Mechanics had signed off that all tools were accounted for as a rotor blade dampener had been replaced prior to the flight. It was a very cold day, -10 deg f at the time of departure. This temperature would have degraded drone performance; however, flight may still have been possible. The ground below the suspected impact was walked to see if any drone or bird parts could be found. There was snow on the ground and an inch had fallen since the impact. Nothing was discovered as FAR as drone or bird parts. No other marks or impacts were discovered on the airframe.
This investigation will be closed as rotor blade impact with an unknown object in flight. Amendment will be made as necessary.
As the FAA filed it
2021-02-13, N352LL, LIFELINKIII AUGUSTA, HELICOPTER TOOK OFF FROM ALEXANDRIA, MN (KAXN) AIRPORT AND HIT AN OBJECT WITH ONE ROTOR BLADE.
AFTER TRANSITIONING STRAIGHT AHEAD TO FORWARD FLIGHT ON RWY 31, THE PIC MADE A LEFT CLIMBING TURN AS DESTINATION WAS SOUTHBOUND. AT AN ALTITUDE BETWEEN 300-400 FT , ALONG THE SOUTHERN BOUNDARY OF THE AIRFIELD, THE PIC HEARD A SINGLE NOISE, AND STATED HE MAY HAVE FELT A MINOR CONTROL MOVEMENT. HE ROLLED OUT AND ASKED THE MEDICAL CREW IN BACK IF SOMETHING HAD FALLEN ON THE FLOOR? THE ANSWER WAS NO.
THE PIC IMMEDIATELY TURNED LEFT AND WAS IN POSITION FOR A LEFT DOWNWIND. HE RETURNED, HAD A PANEL CHECK CONDUCTED AND THEN SHUTDOWN THE AIRCRAFT. WALKAROUND INSPECTION SHOWED A LEADING EDGE ROTOR BLADE IMPACT. THE IMPACT WAS APPROXIMATELY 60 INCHES FROM THE ATTACH POINT ON THE HUB. THE IMPACT WAS ABOUT 1/2 INCH WIDE AND 1/2 INCH DEEP. 6 INCHES AFT OF THE LEADING EDGE IMPACT WAS A HOLE ABOUT 1 INCH THAT PENETRATED THE BOTTOM OF THE BLADE AND EXITED THE TOP, THROUGH THE HONEY COMB AND COMPOSITE MATERIAL. COMPOSITE MATERIAL HAD STARTED TO PEEL AWAY AT A 45 DEGREE ANGLE.
IT WAS UNCLEAR WHAT THE IMPACT COULD HAVE BEEN. NOBODY ON BOARD THE AIRCRAFT HAD SEEN ANYTHING. MECHANICS HAD SIGNED OFF THAT ALL TOOLS WERE ACCOUNTED FOR AS A ROTOR BLADE DAMPENER HAD BEEN REPLACED PRIOR TO THE FLIGHT. IT WAS A VERY COLD DAY, -10 DEG F AT THE TIME OF DEPARTURE. THIS TEMPERATURE WOULD HAVE DEGRADED DRONE PERFORMANCE; HOWEVER, FLIGHT MAY STILL HAVE BEEN POSSIBLE. THE GROUND BELOW THE SUSPECTED IMPACT WAS WALKED TO SEE IF ANY DRONE OR BIRD PARTS COULD BE FOUND. THERE WAS SNOW ON THE GROUND AND AN INCH HAD FALLEN SINCE THE IMPACT. NOTHING WAS DISCOVERED AS FAR AS DRONE OR BIRD PARTS. NO OTHER MARKS OR IMPACTS WERE DISCOVERED ON THE AIRFRAME.
THIS INVESTIGATION WILL BE CLOSED AS ROTOR BLADE IMPACT WITH AN UNKNOWN OBJECT IN FLIGHT. AMENDMENT WILL BE MADE AS NECESSARY.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.