# NTSB CHI05CA240: Piper PA-12, N425AH, Boscobel, WI, August 20, 2005 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: August 19, 2005, 19:00 local (Aug 20, 2005, 00:00 UTC) - Place: Boscobel, WI - Coordinates: 43.160278, -90.675552 - Nearby events: https://openairdocs.org/map.md?lat=43.1603&lon=-90.6756&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report October 27, 2005 - Report: Approved by Office Director - Parties: Milwaukee, WI, FSDO - NTSB case key (mKey): 62363 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI05CA240 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/62363/pdf - Page: https://openairdocs.org/ntsb/CHI05CA240 ## Probable cause The separation of the right main landing gear attachment bracket bolt during the landing and the pilot's aircraft control not possible with the collapsed gear. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, landing - landing gear,main gear attachment - separation (cause) - aircraft control - not possible, pilot in command(cfi) (cause) - On ground/water encounter with terrain/water, landing - terrain condition - runway - terrain condition - ground ## Analysis The tailwheel airplane piloted by a certified flight instructor, sustained substantial damage on impact with terrain when the right main landing gear broke during the landing. The flight instructor stated, "After landing on the hard surface of runway 20, the airplane started a mild left turn towards the grass on the side of the runway. A bolt had broken on the right main gear attach bracket. The right gear folded under the airplane at about 15 mph. The gear broke and pushed the plane up in the air about 5 feet and then fell. The prop stuck in the ground. The wing bent outboard. No injuries." ## Factual narrative On August 19, 2005, about 1900 central daylight time, a Piper PA-12, N425AH, piloted by a certified flight instructor, sustained substantial damage on impact with terrain when the right main landing gear broke during a landing on runway 20 at the Boscobel Airport, near Boscobel, Wisconsin. The instructional flight was operating under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed at the time of the accident. No flight plan was on file. The pilot reported that he and his student were uninjured. The local flight was originating at the time of the accident. The flight instructor's accident report stated: I was giving dual instruction to a private pilot for the purpose of a tailwheel endorsement. After landing on the hard surface of runway 20, the airplane started a mild left turn towards the grass on the side of the runway. A bolt had broken on the right main gear attach bracket. The right gear folded under the airplane at about 15 mph. The gear broke and pushed the plane up in the air about 5 feet and then fell. The prop stuck in the ground. The wing bent outboard. No injuries. ## Aircraft - Registration: [N425AH](https://openairdocs.org/aircraft/N425AH), registered now, S/N 12-817, built 1946 (OpenAirDocs) - Reported make and model: Piper PA-12 - Registry model: [Piper PA-12](https://openairdocs.org/model/piper-pa-12) (registry code 7101202) (OpenAirDocs) - Registry engine: [Lycoming 0-235 series](https://openairdocs.org/engine/lycoming-0-235-series) (registry code 41505, 4 cycle) (OpenAirDocs) - Category: Airplane - Serial number: 12-817 - Airframe hours: 1775 - Engines: Lycoming O-235-C1 108 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Ronald V. Huls - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 1, 2005, 1 hours before - Departed: OVS, Boscobel, WI ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 72; injuries: none; commercial; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review October 1, 2004; flight hours: 19,300 total, 200 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 0° at 0 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 82 °F, dew point 70 °F - Altimeter: 29.86 inHg - Observed at: OVS ## 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 20050819024229A](https://openairdocs.org/incident/20050819024229A), Aug 19, 2005: Piper PA12, Boscobel, WI, Substantial damage. (-23) On 08/19/05, at approximately 1900 CDT, the pilot [privacy data omitted] a flight instructor was giving dual instruction, for a tailwheel endorsement, to… 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.