Trans States Airlines Flight 7495
Aerospatiale ATR 42-300 · Incident: airframe, component or system failure en route
From South Bend International Airport (SBN) to St. Louis Lambert International Airport (STL)
Event
- NTSB case
- CHI00IA221
- 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
- Incident
- 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
- 0
- 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
- Airline
- 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
Aerospatiale ATR 42-300
- Aircraft type
- Aerospatiale ATR-42
- 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
- N421TE
- Operator
- Trans States Airlines
- Onboard fatalities
- Unknown
- Route
- From South Bend International Airport (SBN), South Bend, INTo St. Louis Lambert International Airport (STL), SAINT LOUIS, MO
- Aircraft age
- Not recorded
- 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 121: Air Carrier
- 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 · cruise
- First occurrenceThe 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
- Airframe, component or system failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- None
Cause areas
- Flt control syst, aileron trim/tab control › Contamination
- Flt control syst, aileron trim/tab control › Failure
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The airplane was undamaged during a precautionary landing following a flight control difficulty while in cruise flight. The flight crew was unable to trim the aircraft for level flight. The pilot reported initially that 80 to 100 pounds of control wheel force was required to maintain wings level. Subsequently, the pilot estimated the force required as 50 to 70 pounds. The trim switch was found to be intermittent and subsequent examination confirmed this. The switch was found to be contaminated with, "... salt, dust, hairs and other organic materials." Corrosion of the switch contacts was also found.
Probable cause
The failure of the aileron trim switch due to foreign material contamination.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI00IA221
- Event ID
- 20001212X21375
- Case number
- CHI00IA221
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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, damage. 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: c3e1a5574f43463e4270132e3ca59083939b066989d8b67cf6a4fa77353560a2; retrieved 2026-09-18T16:31:04.652Z.