WPR19LA233 · Cessna 120
Cessna 120 · Accident: loss of engine power (partial) during takeoff
From Livermore Municipal Airport (LVK) to an unrecorded destination
Event
- NTSB case
- WPR19LA233
- 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
Cessna 120
- Aircraft type
- Cessna 120
- 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
- N4237N
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Livermore Municipal Airport (LVK), Livermore, CATo not recorded
- Aircraft age
- About 72 years (built 1947)
- 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
- Takeoff
- 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 engine power (partial)
- 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
- Aircraft › Aircraft power plant
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The accident flight was the first flight following the airplane’s annual inspection. The pilot reported that, during the takeoff roll, the airplane took longer than expected to accelerate, and after becoming airborne, did not seem to be producing full power. Witnesses stated that the airplane made a sharp left turn about 100 feet above the ground and the left wing impacted the ground; the airplane cartwheeled before coming to rest, resulting in substantial damage.
A postaccident examination revealed that the upper and lower spark plugs from the No. 4 cylinder and the lower spark plug from the No. 3 cylinder exhibited oil and soot bridging the gap between the electrodes. All other spark plugs exhibited black soot build-up on the electrodes and insulators. The reason for the fouled spark plugs was not determined based on the examination.
The mechanic who completed the annual inspection reported that he cleaned, gapped, and functionally tested all of the spark plugs. After the inspection, he conducted an engine run-up and found that one of the plugs had become fouled. He cleaned the plugs a second time and reinstalled them using new gaskets. He ran the engine up a second time, and it ran smoothly.
Based on the condition of the No. 4 cylinder spark plugs, it is likely that the engine was not producing nominal power and that its takeoff and climb performance was degraded. The witness observations of a steep left turn and descent to impact is consistent with an aerodynamic stall due to the pilot exceeding the airplane’s critical angle of attack during the initial climb.
Probable cause
A partial loss of engine power due to fouled spark plugs in the No. 4 cylinder. Contributing to the accident was the pilot’s exceedance of the airplane’s critical angle of attack and a subsequent loss of control during the initial climb.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR19LA233
- Event ID
- 20190821X65920
- Case number
- WPR19LA233
- 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: 44f16a81851c466e2be5068a0352ff9e6813987ce38eb136bf389b2431ce22e3; retrieved 2026-09-16T09:50:10.825Z.