What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
199 Robinson R-44 helicopter experienced main rotor and tail rotor failures in flight and sustained substantial damage, other circumstances are unknown. (From .19) on June 11, 1999, about 1715 eastern daylight time, a Robinson R-44, N49669, registered to highway 66 aviation, LLC, dba scenic helicopter tours, operating as a title 14 CFR part 91 sightseeing flight, crashed into a field near Sevierville, Tennessee, after sustaining a main and tail rotor failure while in cruise flight. Visual meteorological conditions prevailed and no flight plan was filed. The aircraft sustained substantial damage and the airline transport-rated pilot and two passengers were uninjured. The flight originated about 20 minutes before the flight. According to the pilot, he was in cruise flight about 400 feet AGL, when he heard a loud "pop" and the helicopter yawed without a control input. Shortly thereafter, he got a low rotor warning horn, both main and tail rotor rpm's went to zero, and he commenced an auto-rotation. He landed in a tobacco field. (.4) the pilot reported that about 10 minutes into his sightseeing flight, at 400 to 500 feet of altitude, in cruise flight, he heard a noise similar to a shotgun blast and experienced vibration, uncommanded yaw, and low rotor and engine RPM. He regained control and conducted a successful autorotation. Postcrash examination of the helicopter revealed drive train, framework, and fuel tank shrapnel damage originating from a failed transmission forward main driveshaft yoke. Examination of the failed yoke by the NTSB materials laboratory revealed a cracked weld that originated during manufacture.
As the FAA filed it
199 ROBINSON R-44 HELICOPTER EXPERIENCED MAIN ROTOR AND TAIL ROTOR FAILURES IN FLIGHT AND SUSTAINED SUBSTANTIAL DAMAGE, OTHER CIRCUMSTANCES ARE UNKNOWN. (FROM .19) ON JUNE 11, 1999, ABOUT 1715 EASTERN DAYLIGHT TIME, A ROBINSON R-44, N49669, REGISTERED TO HIGHWAY 66 AVIATION, LLC, DBA SCENIC HELICOPTER TOURS, OPERATING AS A TITLE 14 CFR PART 91 SIGHTSEEING FLIGHT, CRASHED INTO A FIELD NEAR SEVIERVILLE, TENNESSEE, AFTER SUSTAINING A MAIN AND TAIL ROTOR FAILURE WHILE IN CRUISE FLIGHT. VISUAL METEOROLOGICAL CONDITIONS PREVAILED AND NO FLIGHT PLAN WAS FILED. THE AIRCRAFT SUSTAINED SUBSTANTIAL DAMAGE AND THE AIRLINE TRANSPORT-RATED PILOT AND TWO PASSENGERS WERE UNINJURED. THE FLIGHT ORIGINATED ABOUT 20 MINUTES BEFORE THE FLIGHT. ACCORDING TO THE PILOT, HE WAS IN CRUISE FLIGHT ABOUT 400 FEET AGL, WHEN HE HEARD A LOUD "POP" AND THE HELICOPTER YAWED WITHOUT A CONTROL INPUT. SHORTLY THEREAFTER, HE GOT A LOW ROTOR WARNING HORN, BOTH MAIN AND TAIL ROTOR RPM'S WENT TO ZERO, AND HE COMMENCED AN AUTO-ROTATION. HE LANDED IN A TOBACCO FIELD. (.4) THE PILOT REPORTED THAT ABOUT 10 MINUTES INTO HIS SIGHTSEEING FLIGHT, AT 400 TO 500 FEET OF ALTITUDE, IN CRUISE FLIGHT, HE HEARD A NOISE SIMILAR TO A SHOTGUN BLAST AND EXPERIENCED VIBRATION, UNCOMMANDED YAW, AND LOW ROTOR AND ENGINE RPM. HE REGAINED CONTROL AND CONDUCTED A SUCCESSFUL AUTOROTATION. POSTCRASH EXAMINATION OF THE HELICOPTER REVEALED DRIVE TRAIN, FRAMEWORK, AND FUEL TANK SHRAPNEL DAMAGE ORIGINATING FROM A FAILED TRANSMISSION FORWARD MAIN DRIVESHAFT YOKE. EXAMINATION OF THE FAILED YOKE BY THE NTSB MATERIALS LABORATORY REVEALED A CRACKED WELD THAT ORIGINATED DURING MANUFACTURE.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.