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CHI07CA049 · Beech 99

22 Dec 2006 · Mosinee, WI, United States

Beech 99 · Accident: on ground/water collision with terrain/water during landing

From Wittman Regional Airport (OSH) to Central Wisconsin Airport (CWA)

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Event

NTSB case
CHI07CA049
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
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
Instrument Meteorological Cond

Beech 99

Aircraft type
Beechcraft 99
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
N799CZ
Operator
Unknown
Onboard fatalities
Unknown
Route
From Wittman Regional Airport (OSH), Oshkosh, WITo Central Wisconsin Airport (CWA), Mosinee, 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
Landing
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
On ground/water collision with terrain/water
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 › Unsuitable terrain or takeoff/landing/taxi area, encountered

Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.

NTSB narrative

The airplane, on a non-scheduled domestic cargo positioning flight, sustained substantial damage on impact with a snowbank and terrain during landing. The pilot, in part, stated, "I executed a routine [instrument landing system] approach ... during moderate to heavy snowfall at Central Wisconsin Airport. The runway conditions were reported as poor and it was snow covered. A crosswind existed as well as some wind shear as noted during the approach. Central Wisconsin Tower also advised me of a snow berm that remained on the west side of RWY 35 because it was not plowed to the full width of the runway. After I got a visual on the runway lights, I judged the runway centerlines by the runway lights and my position in between them. After the main wheels touched, I let the nose wheel down and I could see via the landing lights that I was close to the berm on my side and I gradually pushed right rudder pedal to steer away from the snow berm. I did not apply any braking action to avoid skidding and I was above 60 kts and had plenty of runway remaining to bleed off speed. Just as I positioned the power levers in the beta range, the left outer main landing gear tire began to make contact with the edge of the remaining snow berm left by the plows. The aircraft then began to yaw to the left and I applied more right rudder to compensate, but to no avail. The nose wheel hit the snow berm and broke off sending the aircraft sailing over the berm. The main landing gear wheels collapsed completely and the aircraft slid to a stop approximately 200 ft. west of RWY 35 off of the runway."

Probable cause

The pilot encountering the unsuitable terrain during the landing. Factors were the dark night and the snowbank.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record CHI07CA049
Event ID
20070118X00070
Case number
CHI07CA049
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: local date, investigation status, coordinates. Values present in the bulk record are kept.
  • The date is the local date; the NTSB stores the UTC date 2006-12-23.
  • API snapshot SHA-256: 6f15d33cdc8140b38addd3019811d485cbf19eb87424b423672c1d2f2106868d; retrieved 2026-09-22T04:07:00.772Z.