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WPR18LA029 · Bell 206 B

7 Nov 2017 · Rolling Fork, MS, United States

Provine Helicopter Service Bell 206 B · Accident: loss of lift while maneuvering

From Rolling Fork, MS to Rolling Fork, MS

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Event

NTSB case
WPR18LA029
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 206 B

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
N93PH
Onboard fatalities
Unknown
Route
From Rolling Fork, MSTo Rolling Fork, MS
Aircraft age
About 45 years (built 1972)
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 lift
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

No findings designated as a cause are recorded in the NTSB data yet.

Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.

NTSB narrative

The pilot was conducting an aerial application flight. He reported that he was almost finished spraying a river when he suddenly felt the helicopter yaw right then left. Subsequently, he raised the helicopter’s nose up and right to clear a line of trees that ran parallel to the river. When the helicopter reached the height of the treetops, the pilot realized that the airspeed was slow, so he held the collective down to start an autorotation. He then pulled full collective just as the skid impacted the ground hard. The helicopter then came to rest on its right side.

Examination of the helicopter revealed that flight control continuity was established. The tailboom was found fracture separated, consistent with main rotor blade contact. Both main rotor blades exhibited impact damage and warping due to slight spanwise deflection opposite direction of rotation but with low inertia. The 1st-stage compressor inlet and blades exhibited damage consistent with foreign object ingestion. Foreign object damage was also noted in the compressor, and the case was pierced in several areas. Black, sludge-like material that contained aluminum debris was found throughout the gas path from the compressor to the combustor and turbine inlet, and it was mostly along the inner surface of the outer combustion case, consistent with splatter during N1 rotation.

The ingestion of material throughout the engine and foreign object damage to the compressor is consistent with engine operation during the impact sequence. The reason for the uncommanded yaw could not be determined based on the available information because postaccident examination of the airframe, engine and fuel system revealed no evidence of any mechanical malfunctions or failures that would have precluded normal operation.

Probable cause

An uncommanded yaw and subsequent loss of main rotor rpm for reasons that could not be determined.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record WPR18LA029
Event ID
20171108X94652
Case number
WPR18LA029
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, coordinates. 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: f167074a96d479cf3a6fb116aaaab0aa6f8f4b7cd5339ccf47b39f36ee68d268; retrieved 2026-09-16T05:59:34.607Z.