# NTSB CHI94LA176: Snow 600-S2C, N1659S, Bancroft, WI, May 25, 1994 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 25, 1994, 12:00 local (17:00 UTC) - Place: Bancroft, WI - Coordinates: 44.310745, -89.510543 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.3107&lon=-89.5105&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report February 24, 1995 - Report: Approved by Office Director - NTSB case key (mKey): 9544 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI94LA176 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/9544/pdf - Page: https://openairdocs.org/ntsb/CHI94LA176 ## Probable cause the pilots failure to select carburetor heat during an extended descent, which resulted in loss of engine power. Factors were carburetor icing conditions and the presence of a ditch at the forced landing site. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - nonmechanical, descent - normal - weather condition - carburetor icing conditions (contributing factor) - fuel system,carburetor - ice - carburetor heat - not selected, pilot in command (cause) - Forced landing, descent - emergency - On ground/water encounter with terrain/water, landing - roll - terrain condition - ditch (contributing factor) ## Analysis THE PILOT WAS RETURNING FROM A MAINTENANCE CHECK FLIGHT, AND ENTERED A LONG GLIDE TO THE AIRPORT. THE CONDITIONS WERE WITHIN THE AREA OF FAVORABLE CONDITIONS FOR CARBURETOR ICING AT GLIDE POWER ACCORDING TO THE TRANSPORT CANADA CARBURETOR ICING CHART. WHEN THE THROTTLE WAS ADVANCED, THE ENGINE DID NOT PRODUCE POWER AND A FORCED LANDING WAS MADE SHORT OF THE RUNWAY. THE AIRPLANE STRUCK A DITCH. NO PRE-ACCIDENT MECHANICAL DISCREPANCIES WERE DISCOVERED. ## Factual narrative On May 25, 1994, at 1200 central daylight time (CDT), a Snow 600-S2C, N1659S, operated by Farmers Flying Service, Inc., of Bancroft, Wisconsin, impacted a drainage ditch short of the approach end of the runway at the Bancroft East Airport and was substantially damaged. The commercial pilot reported that after an extended glide to descend to the airport, he attempted to increase power, experienced a loss of engine power and made a forced landing. He reported that the propeller was still rotating at impact, but the engine did not produce power. The pilot was not injured. Visual meteorological conditions existed at the time of the accident and no flight plan was filed. The flight was operated under 14 CFR Part 91 as a maintenance check flight following engine installation. Post-crash inspection of the engine revealed no anomalies except 3 broken gear teeth in the supercharger blower gear reduction section. Metallurgical analysis of these gear teeth revealed that all failed due to ductile overstress. During the forced landing, the pilot reported that the propeller struck the ground. Ambient conditions were an outside air temperature of 68 degrees, and a dew point of 57 degrees. This combination of temperatures falls within the area labeled "serious icing - glide power" on the Transport Canada Aviation Safety Bureau chart entitled "Conditions Known Favorable For Carburetor Icing." ## Aircraft - Registration: [N1659S](https://openairdocs.org/deregistered/N1659S-2004-09-13), registration cancelled 2004-09-13, S/N 600-1219C, built 1964 (OpenAirDocs) - Reported make and model: SNOW 600-S2C - Registry model: [Snow 600-S2C](https://openairdocs.org/model/snow-600-s2c) (registry code 8380302) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 12198 - Airframe hours: 6700 - Engines: P&W R-985 450 horsepower reciprocating - Damage: Substantial damage - Flight: Part 91 - Operator: Farmers Flying Service, Inc. - Registered owner: Farmers Flying Service, Inc. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, May 10, 1994, 5 hours before - Airport: 4W11, Bancroft East Airport, runway 18, 2,600 × 24 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 54; commercial; airplane ratings: multi-engine land, single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: center; flight hours: 20,000 total, 5,000 in this make and model, 20,000 as pilot in command, 25 in the last 90 days, 5 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 270° at 7 knots - Visibility: 6 statute miles - Lowest ceiling: 2,100 ft broken - Temperature: 68 °F, dew point 57 °F - Altimeter: 29.00 inHg - Observed at: MSN, 25 nm away ## 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 19940525012519A](https://openairdocs.org/incident/19940525012519A), May 25, 1994: Ayres 600S2C, Rio, WI, Substantial damage. Long glide in from maintenance test flight. Favorable carb icing. Tried add power on final. No go. Hit ditch short. 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.