CEN20LA328 · Bell 206 B
Southwest Heliservices Bell 206 B · Accident: loss of control in flight while maneuvering
From Alpine, TX to an unrecorded destination
Event
- NTSB case
- CEN20LA328
- 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
- 3 · 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
- N284S
- Operator
- Southwest Heliservices
- Onboard fatalities
- Unknown
- Route
- From Alpine, TXTo not recorded
- Aircraft age
- About 42 years (built 1978)
- 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 91: General Aviation
- 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 control in flight
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Aircraft › Aircraft oper/perf/capability
- Not determined › Not determined
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During an aerial survey flight when the helicopter was about 800 ft above ground level, the pilot felt a slight vertical vibration through the collective and airframe. The vibration immediately intensified to a severe lateral vibration in the main rotor system, and the pilot could not control the helicopter. While maneuvering for an emergency landing, the helicopter lost lift and impacted terrain short of the intended landing area, and a postimpact fire ensued. The pilot stated that the engine was producing power at the time of the accident. No evidence indicated an in-flight structural breakup, and all damage to the airframe occurred during the ground impact sequence. A fatigue crack was found on the leading edge abrasion strip of one of the main rotor blades. Given the flat fracture features of the fatigue cracking, the fatigue crack was present before the accident flight. However, this fatigue cracking showed no evidence of propagation into the blade spar and, therefore, was likely not a factor in this accident. The main rotor blade damage was likely due to ground and tailboom impacts; the examined portions of the main rotor blades showed no evidence of an in-flight failure of the main rotor blades. In addition, no evidence showed any flight control disconnections, and further postaccident examination to determine if the flight control system had fractured could not be performed due to the extensive thermal damage. The helicopter’s hydraulic system was unable to be tested due to the damage resulting from the postcrash fire. Examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The reason for the in-flight loss of control could not be determined based on the available evidence for this accident investigation. The helicopter was not equipped with, and was not required to be equipped with, crash resistant flight recorders. The lack of flight recorder data for this accident precluded further evaluation of the accident circumstances and pilot actions. This accident demonstrates the need for crash-resistant flight and image recorders aboard turbine-powered, nonexperimental, nonrestricted-category aircraft that are not currently required to be so equipped, as previously recommended by the National Transportation Safety Board.
Probable cause
The in-flight loss of helicopter control for reasons that could not be determined based on the available evidence.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN20LA328
- Event ID
- 20200808X64216
- Case number
- CEN20LA328
- 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, cause areas. 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: c9bc7ff3dfe393073f526b65e256f414bb9c328e973d089cf8c061e57eda2c15; retrieved 2026-09-15T07:18:09.483Z.