CEN16FA290 · Flight Design Gmbh CTLS
Flight Design Gmbh CTLS · Accident: fuel contamination before flight
From Fond du Lac County Airport (FLD) to an unrecorded destination
Event
- NTSB case
- CEN16FA290
- 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
- 1 · 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
Flight Design Gmbh CTLS
- Aircraft type
- Flight Design CTLS
- 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
- N527TS
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Fond du Lac County Airport (FLD), Fond du Lac, WITo not recorded
- Aircraft age
- About 8 years (built 2008)
- 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 › Aircraft power plant
- Aircraft › Fluids/miscellaneous hardware
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The private pilot departed the airport in the light-sport airplane and made a left turn back toward the airport while still over airport property. The airplane was at a low altitude when it rolled to the left and impacted terrain, consistent with a loss of control following an aerodynamic stall. Witnesses stated that the engine sounded abnormal. One witness reported that the airplane did not climb above treetop height before it rolled into a steep left turn and descended into terrain. An additional witness did not see the accident occur but heard the pilot state on the radio that he was making an immediate return to the airport. The terrain in front of the pilot on departure was commercial properties and parking lots, and was unsuitable for landing.
During postaccident examination, contaminants and corrosion were found in both carburetor bowls. The piston slide in the carburetor for the Nos. 2 and 4 cylinders was found stuck in the idle position in its bore on the carburetor chamber top. A white substance was present on the interior surface of the bore that prevented the piston from sliding up and down within the bore. Testing of the substance determined that it was likely contamination produced by oxidation and corrosion of the aluminum alloy carburetor chamber top because of exposure to water-contaminated fuel. The engine manufacturer had previously issued a Service Instruction (SI) that warned of the possibility of poor performance or engine stoppage due to contaminants in the carburetor float chamber. One of the sources of contaminants identified in the SI was corrosion caused by high water content in fuel. Both carburetors had been inspected in accordance with the SI about 130 flight hours and 19 months before the accident, which was within the SI recommended 200-hour inspection interval. The contaminants found in the carburetors were indicative of the use of fuel with high water content at an undetermined time, most likely after compliance with the SI.
Probable cause
Carburetor contamination following exposure to water in the fuel, which resulted in a carburetor malfunction and a partial loss of engine power. Contributing to the accident was the pilot's loss of airplane control that resulted in a stall.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN16FA290
- Event ID
- 20160728X63145
- Case number
- CEN16FA290
- 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: bcfcec2f22d3651cfea7af31d72bf276b3df975d4469d863bb89978938a0408b; retrieved 2026-09-14T21:57:07.694Z.