What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Accident aircraft was operating under 14 CFR part 137 proceding southwest from the refueling/chemical upload truck at 100 feet AGL. Aircraft demonstrated sudden vibration and loud noises. Pilot related uncertainty of maintaining rotor RPM. Subsequent autorotation and unplanned landing were executed at 32.94059N 115.31871W in an alfalfa field.
ASI observed privacy data omitted upright, in a normal attitude, and appeared undamaged on arrival. ASI found a significant amount of granular FOD as well as substantial amount of 'sand sized'metal shavings on the floor of engine & transmission compartments. Further observation revealed the 'k flex coupling appeared to be fractured/broken and adjacent isolator mount upper metal surface grooved through into the internal rubber medium.
As the FAA filed it
ACCIDENT AIRCRAFT WAS OPERATING UNDER 14 CFR PART 137 PROCEDING SOUTHWEST FROM THE REFUELING/CHEMICAL UPLOAD TRUCK AT 100 FEET AGL. AIRCRAFT DEMONSTRATED SUDDEN VIBRATION AND LOUD NOISES. PILOT RELATED UNCERTAINTY OF MAINTAINING ROTOR RPM. SUBSEQUENT AUTOROTATION AND UNPLANNED LANDING WERE EXECUTED AT 32.94059N 115.31871W IN AN ALFALFA FIELD.
ASI OBSERVED ^PRIVACY DATA OMITTED^ UPRIGHT, IN A NORMAL ATTITUDE, AND APPEARED UNDAMAGED ON ARRIVAL. ASI FOUND A SIGNIFICANT AMOUNT OF GRANULAR FOD AS WELL AS SUBSTANTIAL AMOUNT OF 'SAND SIZED'METAL SHAVINGS ON THE FLOOR OF ENGINE & TRANSMISSION COMPARTMENTS. FURTHER OBSERVATION REVEALED THE 'K FLEX COUPLING APPEARED TO BE FRACTURED/BROKEN AND ADJACENT ISOLATOR MOUNT UPPER METAL SURFACE GROOVED THROUGH INTO THE INTERNAL RUBBER MEDIUM.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.
Other reports on N111PM · 2
Matched to the same aircraft by N-number and date.