# NTSB CHI96LA203: Schweizer G164B, N36311, Oslo, MN, June 15, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 15, 1996, 17:45 local (22:45 UTC) - Place: Oslo, MN - Coordinates: 48.190025, -97.120773 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=48.1900&lon=-97.1208&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report December 16, 1996 - Report: Approved by Office Director - NTSB case key (mKey): 10279 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI96LA203 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/10279/pdf - Page: https://openairdocs.org/ntsb/CHI96LA203 ## Probable cause the pilot not using carburetor heat when the engine began to lose power. Factors in this accident were carburetor ice formation and the soft landing surface the pilot had to use for landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(partial) - nonmechanical, takeoff - initial climb - fuel system,carburetor - ice (contributing factor) - carburetor heat - not used, pilot in command (cause) - Forced landing, emergency descent/landing - altitude - low, pilot in command - Nose over, landing - flare/touchdown - terrain condition - soft (contributing factor) ## Analysis The aerial application flight experienced a gradual power loss during its initial climbout from takeoff. The pilot landed in a field with a soft surface. The airplane nosed over upon touchdown. Examination of the airplane's engine revealed no mechanical aniomalies that would prevent the prodiuction of normal power. The pilot said he had fueled the airplane and checked for water in the fuel before takeoff. He said he had not encountered carburetor ice during previous takeoffs earlier in the day. The pilot said the engine had hesitated on takeoff during the past 2 to 3 weeks. He said it did this on a random basis. The pilot said the airplane's engine had been idling about 5 minutes before takeoff. He said he did not apply carburetor heat when he noticed the power loss. According to an FAA carburetor icing probability chart, the temperature/dew point at the accident site posed a serious threat for carburetor icing at low power settings. ## Factual narrative On June 15, 1996, at 1745 central daylight time (cdt), a Schweizer G164B, N36311, piloted by a commercial pilot, was substantially damaged when it nosed over during a forced landing. The 14 CFR Part 137 flight was not operating on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The pilot was not injured. The flight departed a private airport near Oslo, Minnesota, at 1745 cdt. During an interview with the pilot he said the engine gradually lost power while the airplane was on its initial climb after takeoff. He said he landed on a rain softened field and the airplane nosed over shortly after touchdown. The pilot said the engine had hesitated during acceleration on takeoffs during the past 2 to 3 weeks. He said the hesitation occurances were random. The pilot said he had refueled the airplane and checked the fuel for water before takeoff. He said he did not observe any water or debris in the fuel during the sampling process. He said the power loss was not like it was induced by carburetor ice. The pilot said he had not encountered carburetor icing on earlier flights during the afternoon. The pilot said atmospheric conditions were favorable for carburetor ice formation. The Federal Aviation Administration Principal Avionics Inspector (PAI) representing the NTSB on-scene said he asked the pilot if he had used carburetor heat when he noticed the power loss. The PAI said the pilot told him he did not use the carburetor heat. The PAI said the pilot told him he had been idling the engine on the ground for about 5 minutes before takeoff. The engine's sparkplug electrodes were tan/gray in color. During the engine examination the supercharger impeller could be moved about 10 to 20 degrees along its rotational axis. Further examination revealed the super-charger drive gears were not damaged. The super-charger seal was not damaged. The carburetors float chambers were crushed inward. Both floats were crushed inward about 1/4-inch and pushed against the chamber's walls. Both floats were checked for fuel and pre-impact leaks. The results of the examination were negative. The needle valve seat and carburetor finger screen were clean. Both magnetos produced spark when turned by hand. The temperature/dewpoint at the accident site was 85 and 60 degrees Fahrenheit respectively. Accoridng to the Federal Aviation Aministration's carburetor icing probability chart, these conditions posed a seriuous icing condition for an engine operating at glide power. ## Aircraft - Registration: N36311 (not matched to a registry record) - Reported make and model: Schweizer G164B - Category: Airplane - Serial number: 764B - Airframe hours: 787 - Engines: P&W 1340 600 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Sky Tractor Supply Company - Registered owner: Farmers Union Oil - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, April 26, 1996, 87 hours before - Departed: PVT - Destination: PVT ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 33; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: center; flight hours: 4,300 total, 3,600 in this make and model, 4,100 as pilot in command, 83 in the last 90 days, 80 in the last 30 days, 5 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 130° at 3 knots - Visibility: 15 statute miles - Lowest ceiling: 2,000 ft broken - Temperature: 84 °F, dew point 61 °F - Altimeter: 29.00 inHg - Observed at: GFK, 55 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 19960615026879A](https://openairdocs.org/incident/19960615026879A), Jun 15, 1996: Scwzer G164B, Oslo, MN, Destroyed. Lost power after takeoff for ag operation. Dumped load. Hit ground right wing first. Flipped over. Carb icing. (-23) at 17:45 on June 15, 1996 an model G164B,… 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.