WPR20LA097 · Cessna 170 A
Cessna 170 A · Accident: loss of engine power (partial) en route
From Baker City Municipal Airport (BKE) to Baker City Municipal Airport (BKE)
Event
- NTSB case
- WPR20LA097
- 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 170 A
- Aircraft type
- Cessna 170
- 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
- N5478C
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Baker City Municipal Airport (BKE), Baker City, ORTo Baker City Municipal Airport (BKE), Baker City, OR
- Aircraft age
- About 70 years (built 1950)
- 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
- 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 power plant
- Environmental issues › Physical environment
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that during a local flight, the engine started to knock and vibrate, and the oil pressure indication was low. He initiated a precautionary landing to an open field, and during the landing rollout, the airplane impacted a small ditch, which resulted in substantial damage to the left wing.
A postaccident examination of the engine revealed that the No. 2 connecting rod was separated from the crankshaft. The No. 2 connecting rod journal exhibited thermal distress and mechanical damage. The remaining connecting rod journals and the crankshaft main bearings also exhibited thermal discoloration consistent with oil starvation. When the engine was rotated, no oil flow was observed through the crank journals and lifters. The oil filter screen was covered in dark thick oil and metallic debris and was collapsed.
It is likely that the contaminated oil filter screen collapsed under pressure from the oil pump, which prevented the normal flow of oil through the engine; this resulted in the oil starvation of the No. 2 connecting rod bearing and subsequent separation of the connecting rod from the crankshaft.
Probable cause
The failure of the No. 2 connecting rod bearing as a result of oil starvation due to a contaminated oil filter screen.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR20LA097
- Event ID
- 20200228X92711
- Case number
- WPR20LA097
- 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: 8bb1557db45eb96931953f8bb6012b80cce0ae33a895073c1d8a95be737e8313; retrieved 2026-09-16T11:12:57.443Z.