WPR22LA340 · Bell Helicopter Textron 206L-1
Blue Sky Aviation Bell Helicopter Textron 206L-1 · Accident: flight control system malfunction/failure during landing
Event
- NTSB case
- WPR22LA340
- 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
- Event fatalities
- Unknown
- 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 Helicopter Textron 206L-1
- 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
- N242BH
- Operator
- Blue Sky Aviation
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- Aircraft age
- About 42 years (built 1980)
- 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
- Landing
- 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
- Flight control system malfunction/failure
- 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 propeller/rotor
- Personnel issues › Task performance
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 and two passengers were returning to the base airport following an aerial firefighting mission. During the approach to the airport, the helicopter began an uncontrolled right rotation that could not be arrested despite full use of the left pedal. The pilot attempted to land in the back yard of a private residence; however, the helicopter landed hard and rolled onto its left side. The helicopter sustained substantial damage to the main rotor system, fuselage, and tailboom. An on-scene examination revealed the tail rotor drive shaft had separated at a flex coupling and components critical to the assembly were missing. Postaccident metallurgical examination of tail rotor drive shaft assembly, the pulley, and the recovered hardware revealed that tail rotor drive shaft flange was likely directly attached to the air conditioning pulley flange without a drive ring. The bolt length and recovered hardware would have been adequate to secure the drive shaft flange and the pulley flange together to a drive ring; however, the drive ring, two bolts, six washers and one nut were not found amongst the wreckage after a thorough search. The examination also revealed that the two bolts that were recovered failed from fatigue, likely from the cyclic stress due to the absence of a drive ring. According to the helicopter maintenance records, there had been no recent work on the tail rotor drive shaft or air conditioning unit that would have required disassembly and reassembly of the failed flex coupling.
Probable cause
The improper attachment of the tail rotor drive shaft to the air conditioner drive pulley without a drive ring, which resulted in the failure of the hardware, a loss of tail rotor drive, and the loss of control of the helicopter followed by a hard landing and rollover.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR22LA340
- Event ID
- 20220911105896
- Case number
- WPR22LA340
- 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, 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: bb17148c092ef9110d65d541bfdeb2a5abb896ad13669f97b16fb364a6d29fca; retrieved 2026-09-16T15:57:41.414Z.