Bell UH-1B accident near Arvilla, North Dakota, September 6, 2009
On September 6, 2009 at about 1:05 pm local time, a Bell UH-1B (helicopter), registered N204JB, was substantially damaged in an accident during maneuvering near Arvilla, North Dakota. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The aircraft owner/mechanic/pilot's installation of an improper tail boom assembly and the resulting fatigue failure of the tail boom's attach fittings.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 6, 2009 · about 1:05 pm local time
- Place
- Arvilla, North Dakota · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell UH-1B · all UH-1Bs on the register
- Registration
- N204JB · registry record · serial 63-13088
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
The helicopter pilot reported that he heard a “crack” and a “bang” when he pulled up at the end of the field during the spray run. He stated the helicopter began spinning to the right as it gained altitude. He rolled off the throttle and was able to clear a row of trees at the end of the field. The helicopter impacted the terrain on one side of the tree line and the tail boom was located approximately 100 feet away, on the other side of the tree line. The examination revealed the tail boom’s upper left attach fitting contained fatigue fractures that originated at the upper and lower rivet holes. Corrosion was also present along the fractured surface. The tail boom’s upper right attachment bolt contained a fatigue fracture which had multiple origins. The tail boom’s lower right attach fitting fractured as a result of overload. The tail boom involved in this accident was installed on the helicopter on February 20, 2006, and had been removed from a UH-1F helicopter. The UH-1F tail boom is 23.8 inches longer than the UH-1B tail boom that was originally on the helicopter. The pilot/owner, who is an airframe and powerplant mechanic with inspection authority, performed this maintenance. There is no load data nor is there a Supplemental Type Certificate available for this installation.
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
What happened, in order
- Aircraft structural failure during maneuvering defining event
- Loss of control in flight during maneuvering
- Collision with terrain or object (not controlled flight into terrain) during uncontrolled descent
The NTSB's findings
- cause Aircraft › Aircraft structures › Fuselage › Rotorcraft tail boom › Fatigue/wear/corrosion
- cause Personnel issues › Task performance › Maintenance › Installation › Maintenance personnel
- cause Aircraft › Aircraft structures › Fuselage › Rotorcraft tail boom › Incorrect service/maintenance
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: airplane single-engine; instructor: helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 14,000 hours in all; 1,000 in this make and model; 120 in the last 90 days; 0 in the last 30 days; 13,900 as pilot in command; 1,200 on instruments
- Last flight review: March 10, 2008
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: serious injuries
The aircraft
- Airframe total time: 9,587 hours
- Last inspection: annual inspection, February 6, 2009; 17 hours since
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming T-53L13BA (turboshaft); 0 hours total
The flight
- Departed from: 62ND Larimore ND
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 180° at 7 knots
- Visibility: 7 statute miles
- Sky: clear
- Temperature: 61°F (16°C), dew point 59°F (15°C)
- Altimeter: 30.05 inHg
- Observation at 12:55 pm from GFK, 6 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight 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 N204JB the same tail number, which may have belonged to a different aircraft at the time
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.