# NTSB CHI07CA049: Beech 99, N799CZ, Mosinee, WI, December 23, 2006 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: December 22, 2006, 19:00 local (Dec 23, 2006, 01:00 UTC) - Place: Mosinee, WI - Coordinates: 44.7775, -89.666664 - Nearby events: https://openairdocs.org/map.md?lat=44.7775&lon=-89.6667&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report March 26, 2007 - Report: Approved by Office Director - Parties: Milwaukee, WI, FSDO - NTSB case key (mKey): 65130 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI07CA049 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/65130/pdf - Page: https://openairdocs.org/ntsb/CHI07CA049 ## Probable cause The pilot encountering the unsuitable terrain during the landing. Factors were the dark night and the snowbank. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - On ground/water encounter with terrain/water, landing - unsuitable terrain or takeoff/landing/taxi area - encountered, pilot in command (cause) - facility inadequate, airport personnel - terrain condition - snowbank (contributing factor) - terrain condition - ground - light condition - dark night (contributing factor) ## Analysis 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." ## Factual 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." ## Aircraft - Registration: [N799CZ](https://openairdocs.org/aircraft/N799CZ), registered now, S/N U-68, built 1969 (OpenAirDocs) - Reported make and model: Beech 99 - Registry model: [Beech 99](https://openairdocs.org/model/beech-99) (registry code 1154002) (OpenAirDocs) - Registry engine: [Pratt & Whitney PT6A series](https://openairdocs.org/engine/pratt-whitney-pt6a-series) (registry code 52032, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: U-68 - Airframe hours: 29609 - Engines: Pratt & Whitney PT6A-28 680 horsepower turbo prop; Pratt & Whitney PT6A-28 680 horsepower turbo prop - Damage: Substantial damage - Flight: Positioning, Part 91 - Registered owner: Freight Runners Express Inc - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, December 1, 2006 - Departed: OSH, OSHKOSH, WI - Destination: CWA, Mosinee, WI - Flight plan: IFR - Airport: runway 35, 6,500 × 150 ft, concrete ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 42; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; seat: left; flight hours: 3,500 total, 230 in this make and model, 110 in the last 90 days, 44 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Instrument (IMC), Night/dark - Wind: 280° at 5 knots - Visibility: 1 statute miles - Lowest ceiling: 300 ft overcast - Temperature: 32 °F, dew point 32 °F - Altimeter: 29.56 inHg - Observed at: CWA ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20061222028979A](https://openairdocs.org/incident/20061222028979A), Dec 22, 2006: Beech 99, Mosinee, WI, Substantial damage. (-23) Aircraft landed from an ILS approach at night with one mile visibility in moderate wet snow. Upon landing roll, the aircraft rolled left, striking a… ## Other investigations on N799CZ (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB CEN26LA316](https://openairdocs.org/ntsb/CEN26LA316), Sep 10, 2026: Beech 99 (N799CZ), Belleville, MI, minor damage, investigation ongoing From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.