# NTSB CEN23LA110: Titan Tornado II, N9168P, Windom, MN, February 18, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: February 18, 2023, 12:15 local (18:15 UTC) - Place: Windom, MN · Landed on frozen lake - Coordinates: 46.713346, -92.491301 - Nearby events: https://openairdocs.org/map.md?lat=46.7133&lon=-92.4913&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA - NTSB case key (mKey): 106748 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN23LA110 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/106748/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=106748 - Page: https://openairdocs.org/ntsb/CEN23LA110 ## Probable cause The fatigue failure of the right landing gear leg that resulted in its separation from the airplane during takeoff. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: main landing gear](https://openairdocs.org/ntsb-findings/01023210): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Weber Larry D TITAN TORNADO II, 1 case](https://openairdocs.org/ntsb-findings/01023210/cases.md?model=05902XB), [All aircraft, 241 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Weber Larry D TITAN TORNADO II, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=05902XB), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) ## Analysis The pilot stated that while taking off on a frozen lake with hard-packed snow, the right main landing gear separated from the airplane. He continued the takeoff and landed the airplane without further incident on a snow-covered lake near his home. The airplane sustained substantial damage to the vertical stabilizer due to impact from the right main landing gear. A metallurgical examination of the right main landing gear leg assembly revealed that bilateral fatigue cracks originated from the inner wall of a cross-drilled hole near the right gear leg socket. Eventually, overload and bending stresses in the direction of the fatigue cracks resulted in the right gear leg separating. It was unclear why the hole was drilled. There is an identical hole in the same spot on the left landing gear leg. ## Factual narrative On February 18, 2023, about 1215 central standard time, a Titan Tornado II, N9168P, was substantially damaged when it was involved in an accident near Windom, Minnesota. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he departed Cloquet Airport (COQ) near Cloquet, Minnesota, and flew south to Fish Lake, near Windom, Minnesota, to attend an event. After the event was over, he taxied to an area of the lake where the “snow was hardpacked with no bumps, ruts, or [snow] chunks visible” to take off. After reaching rotation speed, the right main landing gear leg sheared off and struck the vertical stabilizer. The pilot was able to control the airplane with aileron and safely became airborne. The pilot flew back to COQ and advised Duluth Air Route Traffic Control Center that he was going to land on Big Lake, Minnesota, about five miles west of COQ, to prevent any further airplane damage from landing on asphalt. During the landing, he applied full left aileron input and touched down on the left main landing gear wheel first and then lowered the nosewheel. The right wing dropped and slid along the ice. He counteracted with left rudder, spun 90° to the right, and came to a full upright stop. Postaccident examination revealed that the airplane sustained substantial damage to the vertical stabilizer from the impact of the right gear leg after it separated from near the fuselage gear leg socket. An examination of the landing gear revealed that bilateral fatigue cracks originated from the inner wall of a cross-drilled hole near the right gear leg socket. Eventually, overload and bending stresses in the direction of the fatigue cracks resulted in the right gear leg separating. There was an identical hole drilled in each landing gear strut. The purpose of the hole is unknown. The pilot stated the hole was covered by a zip tie that was used to secure the brake line. ## Aircraft - Registration: [N9168P](https://openairdocs.org/aircraft/N9168P), registered now, S/N D00912COHK0376, built 2007 (OpenAirDocs) - Reported make and model: Titan TORNADO II - Registry model: [Weber Larry D TITAN TORNADO II](https://openairdocs.org/model/weber-larry-d-titan-tornado-ii) (registry code 05902XB) (OpenAirDocs) - Registry engine: [Rotax 912S series](https://openairdocs.org/engine/rotax-912s-series) (registry code 55570, 4 cycle) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: D00912COHK0376 - Year built: 2007 - Airframe hours: 1212.8 - Engines: Rotax 912 ULS 100 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental light sport (Special) - Last inspection: Condition, October 1, 2022, 14.7 hours before - Departed: NA, Fredenberg Township, MN - Destination: KCOQ, Cloquet, MN - Equipment: Handheld GPS, Electronic multifunction display ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 66; injuries: none; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; seat: front; flight hours: 1,248.2 total, 1,069.6 in this make and model, 1,198 as pilot in command, 10.4 in the last 90 days, 4.1 in the last 30 days, 1.9 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 210° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 30 °F, dew point 21 °F - Altimeter: 29.96 inHg - Observed at: KCOQ, 7 nm away - METAR: KCOQ 181815Z AUTO 21009KT 10SM CLR M01/M06 A2996 RMK AO2 TSNO ## 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 20230218001429A](https://openairdocs.org/incident/20230218001429A), Feb 18, 2023: Weber Larry D TITAN TORNADO II, Duluth, MN, Substantial damage. 02-18-2023 [privacy data omitted]right main landing gear broke during takeoff from fish lake in Duluth MN. During takeoff from frozen lake with hard packed… ## Docket (3 files) The files NTSB released with the investigation on April 18, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=106748. 37.1 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 15.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15826937&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Materials laboratory factual report (item 2, PDF, 14 pages, 20.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15827343&FileExtension=pdf&FileName=Materials%20Laboratory%20Factual%20Report%2023-055-Rel.pdf - Photos (item 3, PDF, 4 pages, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15827918&FileExtension=pdf&FileName=Photo%20Sheet-N9468T-Rel.pdf 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.