Robinson R-44 accident near Sevierville, Tennessee, June 11, 1999
On June 11, 1999 at about 9:00 pm local time, a Robinson R-44 (helicopter), registered N49669, was substantially damaged in an accident near Sevierville, Tennessee. It was a flight of an unrecorded kind under general aviation rules (Part 91). No one was hurt; 3 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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 processes by the manufacturer and the subsequent autorotative emergency descent and forced landing.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 11, 1999 · about 9:00 pm local time
- Place
- Sevierville, Tennessee · map
- Type
- Accident
- Injuries
- No one was hurt; 3 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Robinson R-44 · all R-44s on the register
- Registration
- N49669 · no longer on the register · serial 562
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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 complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 9,000 hours in all; 100 in this make and model; 70 in the last 90 days; 20 in the last 30 days; 8,700 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 279 hours
- Last inspection: annual inspection, May 19, 1999; 80 hours since
- Maximum gross weight: 2,400 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-540-F1B5 (piston); 0 hours total
The flight
- Departed from: Sevierville TN at 6:50 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 060° at 6 knots
- Visibility: 9 statute miles
- Sky: scat at 6,500 ft
- Temperature: 91°F (33°C), dew point 66°F (19°C)
- Altimeter: 30.00 inHg
- Observation at 8:53 pm from TYS, 24 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.