CEN21LA286 · Ayres Corporation S2R-T34
Ag Solutions Ayres Corporation S2R-T34 · Accident: hazardous material leak/spill while maneuvering
Event
- NTSB case
- CEN21LA286
- 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
Ayres Corporation S2R-T34
- Aircraft type
- Ayres S2
- 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
- N4328P
- Operator
- Ag Solutions
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- Aircraft age
- About 30 years (built 1991)
- 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 137: Agricultural
- 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
- Maneuvering · low-altitude flying
- 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
- Hazardous material leak/spill
- 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 › Fluids/miscellaneous hardware
- Personnel issues › Physical
- Personnel issues › Task performance
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
Before the aerial application flight, the 510-gallon hopper was loaded with 450 gallons of a chemical mixture. While on his second spray pass, the pilot noticed the chemical mixture was reacting and foaming over and out the hooper vent. He climbed the airplane out of his second pass and noticed chemical foaming out of the overflow vent. He looked forward and observed the chemical reacting violently, and it began to emit from the hopper lid. The windshield became fully obscured with foam, and the pilot was unable to see anything outside the airplane. The pilot opened the window in attempt to determine his altitude when the airplane impacted terrain in a wings-level attitude. The airplane skidded on the terrain and came to rest upright.
A postaccident examination of the airplane did not reveal any mechanical anomalies. A jar test of the chemical mixture used in the hopper was not performed by the pilot or the ground loading operations personnel as recommended by the manufacturer of one of the chemicals used. In addition, the technical sheet for one of the chemicals used contained a caution about a chemical foaming reaction when mixing it with other chemicals, one of which was also in the hopper. Due to the pilot’s view being obscured from foam originating from the hopper, the pilot was unable to maintain control and clearance from the terrain during the flight.
Probable cause
The pilot’s loss of visibility in the cockpit due to foam created by the chemicals loaded in the hopper, which resulted in his inability to maintain airplane control during low-level flight and an impact with terrain. Contributing to the accident was the combining of chemicals known to produce foam and the pilot’s failure to perform a jar test before flight as recommended.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN21LA286
- Event ID
- 20210622103313
- Case number
- CEN21LA286
- 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: 9c5af3b3ca4f494ee49677265ad1b3d7586442bb74ab21bdca83ae757785fed1; retrieved 2026-09-16T14:11:57.212Z.