# Accident 19990611007029A: Robsin R44, Sevierville, TN, June 11, 1999

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: June 11, 1999, 17:00 local time
- Place: Sevierville, TN
- Damage: Substantial damage
- Phase of flight: Normal Cruise
- Operating rules: General operating rules (Part 91)
- Location: 35.7796° N, 83.6106° W: From the FAA, an estimate near the named town, within about 3 miles
- Nearby events: https://openairdocs.org/map.md?lat=35.7796&lon=-83.6106&mi=10
- Aircraft: N49669 (not matched to a registry record)
- Reported make and model: ROBSIN R44
- Reported engine: LYC O540F1B5
- People aboard: 3
- Fatal injuries: 0
- Pilot flight hours: 9,000 total, 100 in this make and model, 70 in the last 90 days
- NTSB investigation: [NTSB MIA99LA181](https://openairdocs.org/ntsb/MIA99LA181) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/19990611007029A

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

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.

## The NTSB's investigation of this event (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB MIA99LA181](https://openairdocs.org/ntsb/MIA99LA181), Jun 11, 1999: Robinson R-44 (N49669), Sevierville, TN, substantial damage. Probable cause: The induced fatigue fracture of a component in the engine-to-transmission rotor drive system resulting in a disconnection of the drive system during cruise flight caused by inadequate inspection…

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

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