# NTSB CHI05CA204: Wilson Acrolite 1T, Oshkosh, WI, July 29, 2005 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Data collection · Final report - Date: July 29, 2005, 07:00 local (12:00 UTC) - Place: Oshkosh, WI - Coordinates: 43.984443, -88.556945 - Nearby events: https://openairdocs.org/map.md?lat=43.9844&lon=-88.5569&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report October 27, 2005 - Report: Approved by Office Director - Parties: Federal Aviation Administration - Milwaukee FSDO - NTSB case key (mKey): 62306 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI05CA204 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/62306/pdf - Page: https://openairdocs.org/ntsb/CHI05CA204 ## Probable cause The partial loss of engine power due to an obstructed carburetor fuel metering jet. Factors to the accident included the low altitude at which the loss of engine power occurred, the contamination of the fuel system from degraded automobile-style fuel lines, and the tree that the airplane impacted during the forced 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,line - deteriorated (contributing factor) - obstructed (cause) - altitude - low (contributing factor) - Forced landing, descent - emergency - In flight collision with object, descent - emergency - object - tree(s) (contributing factor) ## Analysis The amateur-built airplane was damaged during a forced landing following a partial loss of engine power during initial climb. The pilot stated that the engine "lost power" during initial climb after takeoff. The pilot reported that the airplane contacted a tree during the subsequent forced landing and then impacted a front yard of a nearby residence. The pilot reported that normal engine operation is around 6,300 rpm during takeoff. The pilot stated that during the accident takeoff the engine was only developing 5,900 rpm. Engine crankshaft and valve continuity was established by rotating the propeller flange during a post-accident examination. Both carburetors were disassembled. The magneto-side carburetor fuel bowl contained several small fragments of black material. The black material was consistent with degraded rubber from an automotive-style fuel line. The engine was outfitted with black rubber, automobile-style fuel lines. The power-takeoff carburetor fuel bowl was void of containments. ## Factual narrative On July 29, 2005, at 0700 central daylight time, an amateur-built Wilson Acrolite 1T, Canadian registry C-IAVT, piloted by a private pilot, was substantially damaged during a forced landing shortly after takeoff from ultralight runway 15 at Wittman Regional Airport, Oshkosh, Wisconsin. Visual meteorological conditions prevailed at the time of the accident. The flight was operating under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91 without a flight plan. The pilot reported minor injuries. The flight was originating at the time of the accident and was destined for Sawyer County Airport (HYR), Hayward, Wisconsin. The pilot reported that he was departing the Experimental Aircraft Association (EAA) AirVenture 2005 convention when the accident occurred. The pilot stated that the engine "lost power" during initial climb after takeoff from ultralight runway 15. The pilot reported that the airplane contacted a tree during the subsequent forced landing and then impacted a front yard of a nearby residence. The pilot reported that normal engine operation is around 6,300 rpm during takeoff. The pilot stated that during initial climb the engine was only developing 5,900 rpm. The engine was examined by representatives of the National Transportation Safety Board and Federal Aviation Administration after the accident. Engine crankshaft and valve continuity was established by rotating the propeller flange. Both carburetors were disassembled. The magneto-side carburetor fuel bowl contained several small fragments of black material. The black material was consistent with degraded rubber from an automotive-style fuel line. The engine was outfitted with black rubber, automobile-style fuel lines. The power-takeoff carburetor fuel bowl was void of containments. ## Aircraft - Registration: C-IAVT (not matched to a registry record) - Reported make and model: Wilson Acrolite 1T - Category: Airplane, amateur-built - Serial number: AC 106 - Airframe hours: 52.2 - Engines: Rotax 582 65 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, November 1, 2004, 11.3 hours before - Departed: OSH, Oshkosh, WI - Destination: HYR, Hayward, WI - Airport: OSH, Wittman Regional Airport, runway 15, 1,200 × ft ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; injuries: minor; private; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review April 1, 2004; seat: center; flight hours: 884 total, 42 in this make and model, 838 as pilot in command, 42 in the last 90 days, 42 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 40° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: 1,600 ft broken - Temperature: 66 °F, dew point 61 °F - Altimeter: 30.14 inHg - Observed at: OSH 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.