# NTSB CHI96LA252: Boeing A75N1, N58712, East Troy, WI, July 21, 1996 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 21, 1996, 10:11 local (15:11 UTC) - Place: East Troy, WI - Coordinates: 42.779342, -88.389343 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.7793&lon=-88.3893&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report August 29, 1997 - Report: Approved by Office Director - NTSB case key (mKey): 10322 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI96LA252 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/10322/pdf - Page: https://openairdocs.org/ntsb/CHI96LA252 ## Probable cause corrosion and fracture of the rudder control horn. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, landing - roll - flt control syst,rudder control - fractured (cause) - flt control syst,rudder control - corroded (cause) - Loss of control - on ground/water, landing - roll - Nose over, landing - roll ## Analysis The pilot reported that he flew a 'normal' approach to land on runway 8. During the landing roll, the airplane began to 'drift' to the right. The pilot 'applied the brakes gently' and the airplane nosed over. Examination of the airplane revealed the left rudder horn was fractured. No other evidence of mechanical malfunction was reported. Metallurgical examintion of the rudder horn 'showed no evidence of progressive cracking, such as fatigue. The fracture was typical of an overstress separation. There was thinning of the wall and corrosion pits on the inside surface of the tube... .' Measurements of some of the corrosion pits revealed that the thickness of the .035 inch wall tubing was corroded to a thickness of .008 inches in some areas. 'There was no indication that any of the corrosion pits had penetrated through the tube to the outside surface.' ## Factual narrative On July 21, 1996, at 1011 central daylight time, a Boeing A75N1, N58712, sustained substantial damage when it nosed over during the landing roll at the East Troy Municipal Airport, East Troy, Wisconsin. The private pilot and one passenger reported no injuries. The personal, 14 CFR Part 91 flight originated in Staughton, Wisconsin, about 0940. Visual meteorological conditions prevailed and no flight plan was filed. The pilot reported that he flew a "normal" approach to land on runway 08. During the landing roll, the airplane began to "drift" to the right. He "applied the brakes gently" and the airplane nosed over. The airplane was inspected by a Federal Aviation Administration (FAA) inspector. He reported that the left rudder horn was fractured. No other evidence of mechanical malfunction was reported. The rudder horn was examined by an engineering technician in the NTSB materials laboratory. In his factual report, the technician reported that the fracture "showed no evidence of progressive cracking, such as fatigue. The fracture was typical of an overstress separation. There was thinning of the wall and corrosion pits on the inside surface of the tube... ." Measurements of some of the corrosion pits revealed that the thickness of the .035 inch wall tubing was corroded to a thickness of .008 inches in some areas. "There was no indication that any of the corrosion pits had penetrated through the tube to the outside surface." ## Aircraft - Registration: [N58712](https://openairdocs.org/aircraft/N58712), registered now, S/N 75-341, built 1941 (OpenAirDocs) - Reported make and model: Boeing A75N1 - Registry model: [Boeing A75N1(PT17)](https://openairdocs.org/model/boeing-a75n1-pt17) (registry code 1380134) (OpenAirDocs) - Registry engine: [Pratt & Whitney R-985 series](https://openairdocs.org/engine/pratt-whitney-r-985-series) (registry code 52008, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 75-341 - Airframe hours: 1900 - Engines: Continental W-670 220 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: John J. Vorndran - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 1, 1995, 13 hours before - Departed: STAUGHTON, WI - Destination: 57C - Airport: 57C, East Troy Municipal, runway 8, 3,900 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 60; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: rear; flight hours: 532 total, 56 in this make and model, 500 as pilot in command, 15 in the last 90 days, 15 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 140° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 19 °F, dew point 14 °F - Altimeter: 30.00 inHg - Observed at: MKE, 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 19960721022799A](https://openairdocs.org/incident/19960721022799A), Jul 21, 1996: Boeing A75N1, East Troy, WI, Substantial damage. (.4)The pilot reported that he flew a 'normal' approach to land on runway 8. During the landing roll, the airplane began to 'drift' to the right. The pilot… ## Other investigations on N58712 (3) 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. - [NTSB DEN76DQD33](https://openairdocs.org/ntsb/DEN76DQD33), Aug 22, 1976: Boeing E75N1 (N58712), Animas, NM, substantial damage - [NTSB SEA69D0245](https://openairdocs.org/ntsb/SEA69D0245), May 6, 1969: Stearman A75 (N58712), Lewiston, ID, substantial damage - [NTSB UNK64X2679](https://openairdocs.org/ntsb/UNK64X2679), Jul 6, 1964: Boeing A75N1 (N58712), Genesee, ID, substantial damage 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.