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).
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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 October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 4, 2003 · about 3:50 pm local time
- 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 |
Other NTSB records under N37799 the same tail number, which may have belonged to a different aircraft at the time
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number SEA03LA125.