CHI91IA223 · Beech B200
Beech B200 · Incident: airframe, component or system failure en route
From General Mitchell International Airport (MKE) to Austin Straubel International Airport (GRB)
Event
- NTSB case
- CHI91IA223
- 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
- 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
Beech B200
- Aircraft type
- Beechcraft 200
- 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
- N770M
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From General Mitchell International Airport (MKE), Milwaukee, WITo Austin Straubel International Airport (GRB), GREENBAY, WI
- 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
- 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
- Minor
Cause areas
- Door, inspection › Separation
- Manufacturer › Acft/equip, inadequate airframe
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE TWIN-ENGINE TURBO PROP AIRPLANE WAS CRUISING AT 8000' MSL, WHEN THE LEFT ENGINE'S OUTBOARD AFT UPPER ACCESSORY CASE COWL DOOR SEPARTED FROM ITS MOUNT. THE COWL DOOR STRUCK THE TOP SURFACE OF THE LEFT WING (OUTBOARD OF THE ENGINE NACELLE) & PENETRATED THE WING'S FUEL CELL. THIS RESULTED IN FUEL SIPHONING & PROMPTED THE PILOT TO PERFORM A PRECAUTIONARY ENGINE SHUTDOWN. THE AIRPLANE WAS LANDED WITHOUT FURTHER INCIDENT. AIRWORTHINESS DIRECTIVE (AD) 91-18-11 (EFFECTIVE 9/3/91) REQUIRED STRUCTURAL MODIFICATION OF THE AFT UPPER COWL ASSEMBLY DOORS TO PREVENT INFLIGHT SEPARATION.
Probable cause
INADEQUATE AIRFRAME DESIGN, WHICH RESULTED IN THE IN-FLIGHT SEPARATION OF THE LEFT ENGINE'S OUTBOARD AFT UPPER COWL DOOR.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI91IA223
- Event ID
- 20001212X17488
- Case number
- CHI91IA223
- 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: 0dd713b0812b59ef3db4e08383ccf755729d38384439717da5cdf593d45c0039; retrieved 2026-09-23T03:54:43.534Z.