CEN20LA263 · Piper PA32 300
Piper PA32 300 · Accident: system/component malfunction/failure (non-power) en route
From Tower Municipal Airport (12D) to Menomonie Municipal Score Field (LUM)
Event
- NTSB case
- CEN20LA263
- 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
Piper PA32 300
- Aircraft type
- Piper PA32
- 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
- N4079R
- Operator
- Zahasky Richard
- Onboard fatalities
- Unknown
- Route
- From Tower Municipal Airport (12D), Tower, MNTo Menomonie Municipal Score Field (LUM), Menomonie, WI
- Aircraft age
- About 52 years (built 1968)
- 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
- En route · cruise
- 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
- System/component malfunction/failure (non-power)
- 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 systems
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The airplane’s engine lost power during cruise flight, and the pilot executed a forced landing to a wooded area. A postimpact fire ensued, and the airplane was destroyed.
Postaccident examination revealed that the engine-driven fuel pump drive shaft had fractured. No other anomalies were found. Further examination of the pump revealed internal corrosion and smeared material on the ends of the pump rotor vanes. The internal bypass spring was missing, but wear marks indicated that the spring had been in place sometime during the life of the pump. The investigation could not determine whether the spring had been removed or was destroyed and consumed internally. Heat discoloration observed on the rotor shaft was consistent with frictional heating of the shaft.
Disassembly of the engine-driven fuel pump revealed that the ends of the rotor vanes that interfaced with the pump sidewalls showed evidence of smeared material, transfer marks, and other oxidized particles, which were consistent with ferrous wear debris. Such contamination of the internal pump components likely resulted in increased friction, frictional heating, and the eventual seizure of the pump, which led to the total loss of engine power during the accident flight. The investigation was unable to determine the source of the contamination based on available evidence.
The engine driven fuel pump was subject to a Mandatory Service Bulletin. The service bulletin introduced pump design enhancements to improve relief valve housing sealing characteristics. These enhancements included actions to ensure that valve cover screws are tightened to correct torque values. The materials examination of the pump showed the gaskets were consistent with unmodified original components indicating the accident fuel pump had not been modified in accordance with the service bulletin. Had the service bulletin been complied with a visual inspection would have revealed gasket protrusion observed between the valve and the pump housing. This would have led to maintenance or replacement of the pump.
Maintenance records were destroyed in the airplane when the accident occurred and hence were not available to substantiate if the service bulletin had been complied with.
Probable cause
The seizure of the airplane’s engine-driven fuel pump due to internal contamination, which led to a total loss of engine power. The source of the contamination could not be determined based on available evidence.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN20LA263
- Event ID
- 20200705X12001
- Case number
- CEN20LA263
- 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: 9fcf38fa85a03f4335cf624402f2f72ac38a27f47c91af321f516625fbeaf192; retrieved 2026-09-16T12:01:52.435Z.