WPR12CA236 · Bell 206B
J.R. Helicopters Leasing Bell 206B · Accident: loss of engine power (total) while maneuvering
From Zillah, WA to Zillah, WA
Event
- NTSB case
- WPR12CA236
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Bell 206B
- Aircraft type
- Bell 206
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N106TV
- Operator
- J.R. Helicopters Leasing
- Onboard fatalities
- Unknown
- Route
- From Zillah, WATo Zillah, WA
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 137: Agricultural
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Maneuvering · low-altitude flying
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of engine power (total)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Aircraft › Aircraft power plant
- Aircraft › Fluids/miscellaneous hardware
- Personnel issues › Action/decision
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During an aerial application flight, the single engine helicopter was flying low over an apple orchard when the engine began to lose power. The pilot decreased his airspeed toward zero and performed a hovering autorotation into the orchard. During the landing, the rotor blades impacted the trees, and the tail boom separated from the main fuselage. An examination of the engine revealed that the compressor discharge pressure (PC) air tube, which connected the PC air filter to the power turbine governor was disconnected. The “B” nut that connected the tube to the PC air filter was present on the tube but not threaded onto the PC air filter boss. The threads on both the PC air filter boss and the “B” nut did not exhibit any damage or abnormalities. Review of the maintenance records showed that, about 6 hours before the accident, the turbine assembly and bleed valve had been replaced. Removal and reinstallation of the PC air tube was conducted as part of the documented maintenance. It is likely that maintenance personnel did not properly torque the “B” nut when reinstalling the tube and the loose “B” nut backed off in-flight. According to the engine manufacturer's technical representative, disconnection of the PC air tube during engine operation would result in a loss of engine power.
Probable cause
The failure of maintenance personnel to properly torque an air tube fitting, which resulted in a total loss of engine power.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR12CA236
- Event ID
- 20120530X22833
- Case number
- WPR12CA236
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: dfcefa21d3d51e9b0a7f6aad5f4c3f4a6c74f87c8907af16ba329636ecfbdbac; retrieved 2026-09-15T18:19:32.264Z.