# NTSB FTW97LA189: Townsend Kitfox, N950AW, Greeley, CO, May 10, 1997 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 10, 1997, 13:57 local (19:57 UTC) - Place: Greeley, CO - Coordinates: 40.439796, -104.670211 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.4398&lon=-104.6702&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report January 7, 1998 - Report: Approved by Office Director - NTSB case key (mKey): 20218 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW97LA189 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/20218/pdf - Page: https://openairdocs.org/ntsb/FTW97LA189 ## Probable cause The engine manufacturer's inadequate quality control by failing to install the harmonic balancer, causing the engine to fail catastrophically. A factor was the lack of suitable terrain on which to make a forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - mech failure/malf, cruise - normal - eng assembly,crankshaft counterweights/vib damper - not installed (cause) - fluid,oil - starvation (cause) - inadequate quality control, manufacturer (cause) - Forced landing, descent - emergency - Hard landing, landing - flare/touchdown - terrain condition - none suitable (contributing factor) ## Analysis The pilot was test flying his experimental airplane in the local area when the engine lost partial power then seized. The airplane landed hard, shearing off the right main landing gear and buckling the fuselage. Post accident disassembly of the engine revealed evidence of high heat distress and a lack of lubrication. The builder said he had adjusted the fuel-oil metering system on previous occasions because the engine was difficult to start and operated erratically. Operating temperatures were also high. The engine was further examined by an independent repair facility. They found that the engine did not have a harmonic balancer, which allowed the crankshaft bearings on the magneto end to move within the crankcase. Extreme internal heat build up and oil starvation damaged the crankshaft bearings, rotary valve, disk, and gear, and caused the connecting rod to eventually fail. ## Factual narrative On May 10, 1997, at 1357 mountain daylight time, a Townsend Kitfox, N950AW, was substantially damaged when it collided with terrain during a forced landing near Greeley, Colorado. The commercial pilot, the only occupant aboard, was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight conducted under Title 14 CFR Part 91. The flight originated at Greeley approximately 1300. According to the pilot, he was in level cruise flight approximately 800 to 1000 feet above ground level when the engine suddenly lost power and seized. The only field available for a forced landing was surrounded by houses and trees. The pilot was able to land in a small field, but the airplane landed hard and sheared off the right main landing gear. The right wing tip contacted the ground and the airplane spun around 180 degrees, buckling the rear fuselage. The Bombardier-Rotax 582 LC engine, s/n 3971294 (a liquid cooled, two cycle, two cylinder, in-line engine with an automatic fuel-oil metering system), was later disassembled at Beegles Aircraft Services in Greeley. The airplane builder was in attendance. Power to the propeller is routed through a gear reduction gearbox. Inside the reduction gearbox, rust and corrosion were found on the output shaft near the rear support bearing. The input gear could be turned by hand with difficulty. After removal of the cylinder head, corroded bolts were found in the cooling jacket. The top inside of the cylinder heads were pitted and burned. Both piston heads, particularly no. 2, were severely burned, and there were metal filings inside no. 2 cylinder. The top of no. 2 piston was pitted and filed down to the compression ring. The sides of no. 2 piston were scored. The exhaust gas temperature probe was discolored. The rotary valve was scarred, and there was a small piece of metal lodged between the valve and its guide. No. 2 main rod bearing and thrust washer were fused together with the rod exhibiting heat damage and discoloration. The rear main bearing was dry. The airplane builder said he adjusted the fuel-air mixture on previous occasions because the engine was difficult to start and operated erratically. Operating temperatures were also high. The engine and fuel-oil metering system was taken to Leading Edge Airfoil in Peyton, Colorado, by the owner's insurance company for examination. According to their report, the engine did not have a harmonic balancer. This allowed the crankshaft bearings on the magneto end to move within the crankcase. Extreme internal heat build up and oil starvation damaged the crankshaft bearings, rotary valve, disk, and gear, and caused the connecting rod to eventually fail. ## Aircraft - Registration: [N950AW](https://openairdocs.org/deregistered/N950AW-1999-12-15), registration cancelled 1999-12-15, S/N 950 (OpenAirDocs) - Reported make and model: Townsend KITFOX - Registry model: [Aero-West Flying Club KITFOX III](https://openairdocs.org/model/aero-west-flying-club-kitfox-iii) (registry code 056186U) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 950 - Airframe hours: 5 - Engines: Rotax 582 LC 65 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: George Townsend & Wayne White - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, January 11, 1997, 5 hours before - Departed: GXY, CO ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 59; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 2,500 total, 12 in this make and model, 1,888 as pilot in command, 5 in the last 90 days, 2 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 79 °F, dew point 19 °F - Altimeter: 30.00 inHg - Observed at: GXY, 1 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 19970510009909A](https://openairdocs.org/incident/19970510009909A), May 10, 1997: Amtrdf KITFOX, Greeley, CO, Substantial damage. Aircraft made emergency landing in a field. 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.