WPR23LA183 · Aero Vodochody L-39ZA
Phantom Phlyers Aero Vodochody L-39ZA · Accident: fuel contamination before flight
From San Angelo Regional Mathis Field (SJT) to an unrecorded destination
Event
- NTSB case
- WPR23LA183
- 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
- Event fatalities
- Unknown
- 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
Aero Vodochody L-39ZA
- Aircraft type
- Aero Vodochody L-39
- 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
- N343WT
- Operator
- Phantom Phlyers
- Onboard fatalities
- Unknown
- Route
- From San Angelo Regional Mathis Field (SJT), San Angelo, TXTo not recorded
- Aircraft age
- About 37 years (built 1986)
- 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
- Prior to flight
- 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
- Fuel contamination
- 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
- Not determined › Not determined
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot stated that after taking off and climbing through about 7,300 ft mean sea level (msl), he heard a “pop” noise. He scanned the engine instruments and saw them “rolling back.” The pilot pitched the airplane for best glide and attempted to restart the engine, which was unsuccessful. Unable to restart the engine, the pilot performed a forced landing to a dirt road in a field, which resulted in substantial damage to both wings. The pilot reported that he had flown to the departure airport the day before the accident, had the airplane refueled with 342 gallons of fuel, and had the airplane secured in a hangar before taking off for the accident flight. A postaccident examination of the airplane and engine revealed no mechanical anomalies with the engine or airframe that would have contributed to a loss of engine power. Fuel recovered from the airplane fuel sump after the accident was tested for contaminants. Water was detected in that fuel sample at a rate of 55 parts per million (ppm), which is considered an acceptable level. However, recovery personnel stated that when the airplane was de-fueled during the recovery process, the ½ gallon capacity fuel-water separator filter clogged and filled with water 3 times. The recovery personnel further stated the airplane had not been rained on after the accident and before recovery. Fuel was tested from the source where the airplane was refueled before the accident flight and water was detected at less than 15 ppm and no fuel related issues were reported by the operators of the other aircraft refueled from the same source. Fuel is capable of absorbing water directly from the atmosphere via the ventilation system of the fuel system/storage tank or through condensation in the tank. However, investigators were not able to verify if that occurred. The circumstances of the accident, coupled with the finding of undissolved water in the fuel during the recovery of the airplane, is consistent with a total loss of engine power due to fuel contamination. However, the source of the water in the fuel could not be determined based on available evidence.
Probable cause
A total loss of engine power due to water-contaminated fuel from an undetermined source.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR23LA183
- Event ID
- 20230509122573
- Case number
- WPR23LA183
- 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, coordinates, 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: 79cc3f7a8022ab3fbb728f920c104edcbca56eed95ad5bc3154efe4abbbc45c9; retrieved 2026-09-16T17:35:13.238Z.