CEN20LA169 · Rans S-12
Rans S-12 · Accident: loss of control in flight on approach
From Blake Field (AJZ) to Blake Field (AJZ)
Event
- NTSB case
- CEN20LA169
- 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
- 1 · 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
Rans S-12
- Aircraft type
- Rans S-12
- 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
- N427LB
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Blake Field (AJZ), Delta, COTo Blake Field (AJZ), Delta, CO
- Aircraft age
- About 16 years (built 2004)
- 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
- Approach · VFR pattern final
- 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
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot of the test flight was attempting to correct airplane stability issues before the flight. A witness assumed that the pilot was planning to perform a high-speed taxi test rather than flight, and that the airplane’s takeoff was unintentional. After takeoff, the airplane was seen in the airport traffic pattern at 300-400 ft above ground level. Witnesses then observed the airplane change pitch and bank while the engine was heard increasing to full power and then decreasing. The airplane stalled, impacted terrain, and was destroyed by impact forces.
Post-accident examination of the airplane confirmed flight control and engine continuity. There were four ballast bags (about 25 lbs each) and two dumbbell weights (marked 35 lbs). All the ballast bags and one dumbbell weight were in the passenger seat area. High-speed taxi testing is not a test area of aircraft stability and control. Given the pilot’s previous statement of his intentions and the presence of ballast/weights in the passenger seat area, it is likely that he was experimenting with airplane stability and control when the airplane exceeded its critical angle of attack, which led to an aerodynamic stall.
Probable cause
The pilot’s exceedance of the airplane’s critical angle of attack during a test flight which resulted in an aerodynamic stall and impact with terrain.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN20LA169
- Event ID
- 20200503X45457
- Case number
- CEN20LA169
- 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: a2e8ef35dd82dd4cd9b64986de6ec7f760906a8cb30de29129c49712201221f1; retrieved 2026-09-15T07:14:07.337Z.