# NTSB DEN04LA070: Crimmins Smyth Sidewinder, N92AC, Natrona, WY, May 7, 2004 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 7, 2004, 12:30 local (18:30 UTC) - Place: Natrona, WY - Coordinates: 43.049999, -106.783332 - Nearby events: https://openairdocs.org/map.md?lat=43.0500&lon=-106.7833&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 29, 2004 - Report: Approved by Office Director - Parties: FAA Flight Standards Field Office - NTSB case key (mKey): 59184 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN04LA070 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/59184/pdf - Page: https://openairdocs.org/ntsb/DEN04LA070 ## Probable cause fuel starvation due to contamination, resulting in the fuel selector valve becoming totally blocked. Contributing factors were the inadequate conditional inspection, and the lack of nsuitable 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, cruise - normal - fluid,fuel - contamination (cause) - maintenance,inspection - inadequate, other maintenance personnel (contributing factor) - fuel system,selector/valve - blocked(total) (cause) - fluid - starvation - Forced landing, descent - emergency - On ground/water encounter with terrain/water, landing - roll - terrain condition - none suitable (contributing factor) ## Analysis After refueling to capacity, the pilot took off to ferry his newly-purchased airplane it to his home base. After 1 hour in cruise flight at 9,500 feet msl, the engine --- which had been producing 2,500 rpm --- began "surging" and started losing power. Carburetor heat was opened and the mixture was adjusted, but the engine continued to lose power. Cylinder head temperature, oil temperature, and oil pressure indicated normal parameters. As the airplane began losing altitude, the pilot decided to land in an open area. During the landing rollout, the nose and right main landing gears were torn off, and the left main landing gear folded underneath the airplane. The firewall was buckled and there was wing damage. Later examination of the fuel selector valve a considerable amount of fine grit inside the fuel screen. Similar grit was seen inside the fuel tank. The airplane was given a conditional inspection on May 6, 2004. Prior to that, the last conditional inspection was on August 1, 1996. Tachometer time between these two inspections was 178.9 hours. At the last inspection, the fuel tank was removed, cleaned by a radiator shop, and reinstalled in the airplane. ## Factual narrative On May 7, 2004, approximately 1230 mountain daylight time, a Crimmins Smyth Sidewinder, N92AC, operated by the pilot, was substantially damaged during a forced landing following a loss of engine power 1 mile east of Natrona, Wyoming. The commercial pilot, the sole occupant on board, was not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the ferry flight being conducted under Title 14 CFR Part 91. The flight originated at Thermopolis, Wyoming, approximately 1130, and was en route to Aurora, Colorado, with a planned refueling stop in Casper, Wyoming. In his accident report, the pilot stated that he had just purchased the airplane and was ferrying it to his home base. He had flown the airplane for a total of 5 hours (3.5 hours the day before the accident, and 1.5 hours on the day of the accident) with the previous owner. After refueling the airplane to capacity, the pilot departed Thermopolis Airport (THP) at approximately 1130, en route to Casper, Wyoming. While in cruise flight at 9,500 feet msl, the engine --- which had been producing 2,500 rpm --- began "surging" and started losing power. Carburetor heat was opened and the mixture was adjusted, but the engine continued to lose power. The pilot said the cylinder head temperature, oil temperature, and oil pressure indicated normal parameters. As the airplane began losing altitude, the pilot decided to land in a field. During the landing rollout, the nose and right main landing gears were torn off, and the left main landing gear folded underneath the airplane. The firewall was buckled and both wings were crushed. According to the airplane maintenance records, the airplane was given a conditional inspection and found to be in an airworthy condition on May 6, 2004, at a tachometer reading of 596.6 hours. Prior to that, the last conditional inspection was on August 1, 1996, at a tachometer reading of 417.7 hours. Tachometer time between these two inspections was 178.9 hours. At the last conditional inspection, the fuel tank was removed, cleaned by a radiator shop, and reinstalled in the airplane. On June 23, 2004, the airplane was examined at Beegles Aircraft Service in Greeley, Colorado. The fuel line between the fuel selector valve and the gascolator was removed and examined. No obstructions were noted. When the fuel selector valve was removed from the fuel tank, approximately 1-2 quarts of fuel poured out. Examination of the fuel selector (which the pilot had placed in the OFF position after the accident) revealed a considerable amount of fine grit inside the fuel screen. Similar grit was seen inside the fuel tank. ## Aircraft - Registration: [N92AC](https://openairdocs.org/deregistered/N92AC-2013-07-30), registration cancelled 2013-07-30, S/N 212380, built 1977 (OpenAirDocs) - Reported make and model: Crimmins Smyth Sidewinder - Registry model: [Crimmins SMYTH SIDEWINDER](https://openairdocs.org/model/crimmins-smyth-sidewinder) (registry code 0564923) (OpenAirDocs) - Registry engine: [Lycoming 0-290 series](https://openairdocs.org/engine/lycoming-0-290-series) (registry code 41506, 4 cycle) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 212380 - Airframe hours: 601 - Engines: Lycoming O-290-G-D 135 horsepower reciprocating - Damage: Substantial damage - Flight: Ferry, Part 91 - Registered owner: William J. Harris - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, May 6, 2004, 4 hours before - Departed: THP, Thermopolis, WY - Destination: CPR, Casper, WY ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 36; injuries: none; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; last flight review September 12, 2003; seat: left; flight hours: 750 total, 6 in this make and model, 600 as pilot in command, 30 in the last 90 days, 10 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 240° at 18 knots, gusting 24 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 81 °F, dew point 21 °F - Altimeter: 30.03 inHg - Observed at: CPR, 22 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 20040507009249A](https://openairdocs.org/incident/20040507009249A), May 7, 2004: Amtr SIDEWINDER, Natrona, WY, Substantial damage. (-23) On a flight from thermopolis, Wyoming to casper, Wyoming at a cruise altitude of 9,500 feet MSL the engine, which had been producing 2500 RPM, began… 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.