WPR18LA206 · Bell UH 1H
Bell UH 1H · Accident: loss of control in flight during landing
From Madera Municipal Airport (MAE) to Lincoln Regional Karl Harder Field (LHM)
Event
- NTSB case
- WPR18LA206
- 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 UH 1H
- Aircraft type
- Bell UH-1
- 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
- N107CH
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Madera Municipal Airport (MAE), Madera, CATo Lincoln Regional Karl Harder Field (LHM), Lincoln, CA
- Aircraft age
- About 51 years (built 1967)
- 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 · flare/touchdown
- 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
- Substantial
Cause areas
- Aircraft › Aircraft oper/perf/capability
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During a cross-country flight, the helicopter started to produce an unusual noise. The pilot initiated a precautionary landing and the noise became louder. About 5 ft off the ground before touchdown, the helicopter entered an uncontrolled climb and yaw. The pilot was unable to recover from the loss of directional control and the helicopter subsequently impacted terrain. Examination of fractured pieces from the main rotor drive shaft and the swashplate assembly exhibited features consistent with fracture from overstress; however, it is likely that this damage was sustained during the impact. Although it is possible that one of the components may have failed from overstress in-flight, this would have required an abnormally high load input to one or more components. The exam did not reveal any evidence of mechanical malfunctions or anomalies that would have precluded normal operation of the helicopter, and the source of the noise reported by the pilot could not be determined.
Probable cause
The pilot's loss of control during a precautionary landing following an abnormal noise in-flight, the source of which could not be determined.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR18LA206
- Event ID
- 20180724X30725
- Case number
- WPR18LA206
- 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: eae56e11fb0c489fe56a707e53345fe1115f240f1947c78c6a63442911c10fbf; retrieved 2026-09-16T07:57:51.240Z.