WPR17LA094 · Yakovlev YAK 52
Yakovlev YAK 52 · Accident: loss of engine power (partial) en route
From Porterville Municipal Airport (PTV) to Porterville Municipal Airport (PTV)
Event
- NTSB case
- WPR17LA094
- 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
Yakovlev YAK 52
- Aircraft type
- Yakovlev YAK-52
- 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
- N132MD
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Porterville Municipal Airport (PTV), Porterville, CATo Porterville Municipal Airport (PTV), Porterville, CA
- Aircraft age
- About 34 years (built 1983)
- 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 › Fluids/miscellaneous hardware
- Environmental issues › Physical environment
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The airline transport pilot reported that, during a formation flight, the engine started to run rough. Unable to maintain level flight, the pilot detached from the formation to troubleshoot the problem. The pilot noted that there were about 29 gallons of useable fuel onboard and all other indications were normal. The engine continued to lose power, and about 500 ft above the ground, the pilot elected to land in a vineyard. During landing, the airplane touched down, came to an abrupt stop, nosed over, and came to rest inverted.
Postaccident engine examination revealed small pieces of fabric in the fuel screen. In addition, some metal shavings and a small piece of metal were found in the fuel intake and carburetor inlet screen. The origins of the metal piece and shavings could not be determined. It is unlikely that the observed debris was enough to clog the fuel system; however, it is possible that there were other, non-observable pieces of debris in the fuel system that could have resulted in decreased fuel flow and the partial loss of engine power.
Probable cause
A partial loss of engine power due to contaminants in the fuel system that decreased the fuel flow, the source of which could not be determined.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR17LA094
- Event ID
- 20170501X11122
- Case number
- WPR17LA094
- 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: 84d243d26f194cd5f3aaffd7b09f817989df6bdce9018b345d8f4c9d1cc7d57c; retrieved 2026-09-16T05:12:44.255Z.