Sikorsky UH-19D accident near La Grande, Oregon, July 4, 2003
On July 4, 2003 at about 3:50 pm local time, a Sikorsky UH-19D (helicopter), registered N37799, was destroyed in an accident near La Grande, Oregon. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The cross threading and separation of the clutch assembly while maneuvering which resulted in a loss of engine power followed by a hard landing. An inadequate maintenance overhaul was a factor.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 4, 2003 · about 3:50 pm local time · cases in 2003
- Place
- La Grande, Oregon · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Sikorsky UH-19D · all UH-19Ds on the register
- Registration
- N37799 · no longer on the register · serial 56-1542
- Damage
- Destroyed
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
During an aerial application flight, the pilot reported that during a turn he heard and felt three or four "clunking sounds in the airframe." The pilot continued the pedal turn to the left and then straightened out to approach a field. Rotor rpm was deteriorating as he attempted to auto rotate to the field. The pilot stated that he had "no auto-rotating capability" and landed hard in the field. The helicopter bounced once then touched down again coming to rest on its left side. A post-crash fire consumed the wreckage. On site inspection of the wreckage found that the free wheeling side of the clutch assembly and the main drive shaft assembly nut were disconnected. The items were sent to the NTSB materials laboratory for further inspection. The specialist reported that the drive from the main rotor gearbox to the clutch was severed when the bearing support separated from the drive housing. The threads on the bearing support displayed a shearing off of the crown of the forward full form thread. The flanks of the threads to the rear of the sheared thread displayed no indications of contact by the mating thread on the drive housing. Mechanical damage to the threads on the drive housing was limited to the first two rearmost threads. The flanks of the threads forward of the damaged threads displayed no indications of contact by the mating thread on the bearing support. Deformation of the rear ends of the splines forward of the threads and of the two rearmost threads indicate that it was not fully engaged with the drive housing.
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: commercial pilot
- Ratings: rotorcraft: helicopter
- Flight time: 2,800 hours in all; 460 in this make and model; 100 in the last 90 days; 30 in the last 30 days; 2,720 as pilot in command
- Last flight review: June 12, 2002
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
- Injury: no injuries
The aircraft
- Last inspection: approved inspection programme, September 4, 2002; 114 hours since
- Maximum gross weight: 7,900 lb
- Seats: 2
- Landing gear: fixed
- Engine: Curtis Wright R1300-3D (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: LGD La Grande OR
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 63°F (17°C), dew point 37°F (3°C)
- Altimeter: 30.12 inHg
- Observation at 4:15 pm from LGD, 5 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
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.
Other NTSB records under N37799 the same tail number, which may have belonged to a different aircraft at the time
Connections how this case links to the rest of the register
- N37799: not on the register today · the record of its deregistration
- Sikorsky UH-19 7 registered today · the model family and its accident history
- Sikorsky 825 aircraft on the register
- Engine: Curtis Wright R1300-3D · as the NTSB recorded it
- LA Grande/Union County · departed from
- Accidents and incidents in Oregon 1,864 since 1982 · 279 in the last ten years
- Oregon 7,011 aircraft registered
- Other NTSB records under N37799 1 records · the number may have belonged to another aircraft at the time
The whole map of how records connect · these connections as data: /graph/accident/SEA03LA125.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.