# NTSB CHI00LA189: Staudacher S-300D2, N112KG, Kenosha, WI, July 7, 2000 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 7, 2000, 18:00 local (23:00 UTC) - Place: Kenosha, WI - Coordinates: 42.619201, -87.829864 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.6192&lon=-87.8299&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 26, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 49777 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI00LA189 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/49777/pdf - Page: https://openairdocs.org/ntsb/CHI00LA189 ## Probable cause The fatigue failure of the rod end bearing and the separation of the aileron. A factor was the inadequate design change by the aircraft designer. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, maneuvering - flight control,aileron attachment - fatigue (cause) - maintenance,design change - inadequate, production/design personnel (contributing factor) - flight control,aileron - separation (cause) ## Analysis The pilot was performing a 1/2 snap roll when the left aileron departed the airframe. The aircraft was still controllable and an uneventful landing was made. The spherical rod end bearing that was used for the center aileron hinge had broken and a subsequent metallurgical was performed. Energy dispersive spectroscopy (EDS) examination revealed "... only iron and manganese consistent with plain carbon steel. There were no appreciable amounts of chromium, nickel, or molybdenum as might be expected with an AISI 4130 or AISI 8420 material." The report also states that the "... microstructure and hardness is typical of a normalized or annealed, medium carbon steel." The metallurgical report states that the rod end fracture was due to "... reverse bending fatigue (from cycling about its lateral axis) initiating at the root of the shank threads." The aircraft designer said that the accident aircraft had a different style rod bearing installed than the original design. The designer stated that he believed that the new rod end bearing shank was made of the same material and heat treat as the original. The specification for the original rod end bearing shows that the shank is to be made from AISI 4130 or AISI 8420 steel. ## Factual narrative On July 7, 2000 at 1800 central daylight time, a Staudacher S-300D2, N112KG, piloted by an airline transport pilot, sustained substantial damage while performing aerobatics near Kenosha, Wisconsin. The 14 CFR Part 91 flight was not on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The pilot, who was the sole occupant, was not injured. The flight originated from the Kenosha Regional Airport, Kenosha, Wisconsin, at an undetermined time, for a local flight. According to the pilot, he had been practicing aerobatic maneuvers and was performing a 1/2 snap roll when the left aileron departed the airframe. The pilot said that the aircraft was still controllable and an uneventful landing was made. A postaccident examination of the airframe revealed that the spherical rod end bearing that was used for the center hinge had broken. The inboard 1-foot of the aileron and the inboard hinge remained attached to the wing. The outboard 6-inches of aileron spar as well as the outboard hinge remained attached to the wing. No other aileron pieces have been recovered. A metallurgical examination of the remaining portion of the spherical rod end bearing that was used for the center hinge was performed. Energy dispersive spectroscopy (EDS) examination revealed "... only iron and manganese consistent with plain carbon steel. There were no appreciable amounts of chromium, nickel, or molybdenum as might be expected with an AISI 4130 or AISI 8420 material." The report also states that the "... microstructure and hardness is typical of a normalized or annealed, medium carbon steel." The metallurgical report states that the rod end fracture was due to "... reverse bending fatigue (from cycling about its lateral axis) initiating at the root of the shank threads." Telephone interviews with the aircraft designer revealed that the accident aircraft had a different style rod bearing installed than the original design. The designer stated that he believed that the new rod end bearing shank was made of the same material and heat treat as the original. The specification for the original rod end bearing shows that the shank is to be made from AISI 4130 or AISI 8420 steel. ## Aircraft - Registration: [N112KG](https://openairdocs.org/aircraft/N112KG), registered now, S/N 22 (OpenAirDocs) - Reported make and model: Staudacher Aircraft, Inc. S-300D2 - Registry model: [Staudacher S-300D2](https://openairdocs.org/model/staudacher-s-300d2) (registry code 0560699) (OpenAirDocs) - Registry engine: [Lycoming IO-540 series](https://openairdocs.org/engine/lycoming-io-540-series) (registry code 41530, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 22 - Airframe hours: 393 - Engines: Lycoming IO-540-G1D5 330 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Richard Martinez - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, February 1, 2000, 41 hours before - Departed: ENW ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 37; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: center; flight hours: 8,430 total, 309 in this make and model, 3,047 as pilot in command, 200 in the last 90 days, 75 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 140° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: 25,000 ft broken - Temperature: 151 °F, dew point 131 °F - Altimeter: 30.00 inHg - Observed at: MKE ## 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 20000707037179A](https://openairdocs.org/incident/20000707037179A), Jul 7, 2000: Amtr S300D2, Kenosha, WI, No damage. (-23) While performing aerobics (1/2 snap to left) left aileron departed the aircraft. Investigation revealed center aileron hinge had failed. Landed without… 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.