CEN20LA259 · Sopwith Type 9400
Sopwith Type 9400 · Accident: flight control system malfunction/failure while maneuvering
Event
- NTSB case
- CEN20LA259
- 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
Sopwith Type 9400
- Aircraft type
- Sopwith TYPE 9400
- Category
- Airplane
- 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
- N5539
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- Aircraft age
- About 1 year (built 2019)
- 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
- 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
No findings designated as a cause are recorded in the NTSB data yet.
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During a test flight the pilot moved the control stick fully to the right to roll out of a turn, but the airplane did not respond, and the pilot suspected a failure in the aileron controls. The airplane eventually rolled wings level and the pilot elected to perform an emergency landing to a corn field, during which the airplane hit a tree and descended into the field. The wings and fuselage were substantially damaged during impact.
The pilot, who was also the builder of the airplane, examined the wreckage and determined that a rocking tube that connected the front cockpit control stick to the rear control stick had moved rearward about 1 inch. The aileron cables connected to a horn affixed to this tube. The rearward movement of the rocking tube was sufficient for the front part of the tube to come loose from its socket, which likely affected the control authority of the ailerons and resulted in the pilot’s inability to control the airplane. The pilot explained that there was nothing in the original design that prevented the rocking tube from sliding aft.
Probable cause
An inflight loss of aileron control due to movement of a control connector.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN20LA259
- Event ID
- 20200703X75509
- Case number
- CEN20LA259
- 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: 15b8b965b757a8e11a51fab9cd8e23f0990ffec01606d9db6f610b63f512939a; retrieved 2026-09-16T12:00:37.445Z.