CHI91LA270 · Cessna 150L
Cessna 150L and Aeronca 11CC · Accident: midair collision en route
Event
- NTSB case
- CHI91LA270
- 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
- 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
- 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
Aircraft 1 · Cessna 150L
- Aircraft type
- Cessna 150
- 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
- N16098
- Operator
- Ralph Hurlbert
- Onboard fatalities
- Unknown
- Route
- From Clark County Airport (8D7), Clark, SDTo Watertown Regional Airport (ATY), Watertown, SD
- 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 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 · 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
- Midair collision
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Aircraft 2 · Aeronca 11CC
- Aircraft type
- Aeronca 11
- 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
- N4535E
- Operator
- Colman L. Wagner · private individual
- Onboard fatalities
- Unknown
- Route
- From Clark County Airport (8D7), Clark, SDTo not recorded
- 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 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 · 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
- Midair collision
- 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
- Pilot in command › Formation flying, attempted
- Pilot of other aircraft › Formation flying, attempted
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
TWO AIRPLANES COLLIDED WHEN THE PILOT OF AN OVERTAKING AIRPLANE N16908 ATTEMPTED TO JOIN AND FLY FORMATION WITH THE LEAD AIRPLANE N4535E. THE PILOT OF THE LEAD AIRPLANE WAS NOT AWARE OF THE OVERTAKING AIRPLANE. BOTH PILOTS PERFORMED EMERGENCY LANDINGS.
Probable cause
ATTEMPTED FORMATION FLYING WITH N4535E BY THE PILOT OF N16098. FACTORS ASSOCIATED WITH THE COLLISION WERE: NONPERFORMANCE OF PREFLIGHT PLANNING, AND FAILURE TO FOLLOW PROCEDURES AND DIRECTIVES BY THE PILOT OF N16098.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI91LA270
- Event ID
- 20001212X17829
- Case number
- CHI91LA270
- 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. 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: 0c8312eff57959561436f3504cf1cfc882ba2bf0b48c9f71791c9f22ac0acb65; retrieved 2026-09-21T23:28:01.870Z.