# NTSB WPR09CA134: Kreps Thorp T-18-C, N118CK, Palm Springs, CA, March 1, 2009 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: February 28, 2009, 16:10 local (Mar 1, 2009, 00:10 UTC) - Place: Palm Springs, CA - Coordinates: 33.816665, -116.511108 - Nearby events: https://openairdocs.org/map.md?lat=33.8167&lon=-116.5111&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report June 11, 2009 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FAA-RAL-FSDO - NTSB case key (mKey): 73414 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR09CA134 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/73414/pdf - Page: https://openairdocs.org/ntsb/WPR09CA134 ## Probable cause A loss of directional control due to the fatigue failure of a tubular steel gear leg along a corroded weld line. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: tube](https://openairdocs.org/ntsb-findings/01023245): Aircraft › Aircraft systems · Fatigue/wear/corrosion (probable cause); cases with it: [Kreps Curtis D. THORP T-18, 1 case](https://openairdocs.org/ntsb-findings/01023245/cases.md?model=89510F6), [All aircraft, 19 cases](https://openairdocs.org/ntsb-findings/01023245/cases.md) - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Kreps Curtis D. THORP T-18, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=89510F6), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-landing roll: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Kreps Curtis D. THORP T-18, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=89510F6), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Landing-landing roll: Loss of control on ground](https://openairdocs.org/ntsb-events/230); cases with it: [Kreps Curtis D. THORP T-18, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=89510F6), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Kreps Curtis D. THORP T-18, 1 case](https://openairdocs.org/ntsb-events/300/sequence.md?model=89510F6), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) ## Analysis The pilot of the tailwheel-equipped experimental airplane had just touched down for a full-stop landing when the airplane started veering to the left. Although the pilot applied rudder and brake inputs to correct the airplane's alignment, the airplane did not respond. The pilot then added power to help correct the veering, but the airplane departed the left side of the runway and impacted a runway/taxiway sign. A postaccident inspection of the tubular steel left gear leg revealed that it had partially failed along a corroded weld line, and had bent backwards from its normal position. Corrosion/rust was present on about one inch of the fracture face, and along a wider area of the interior wall of the gear leg adjacent to the fracture. The fracture itself continued around about 70 percent of the circumference of the tubular leg. ## Factual narrative The pilot of the tail wheel-equipped experimental airplane had just touched down for a full stop landing when the airplane started veering to the left. Although the pilot, who had about 420 flight hours in the airplane, applied rudder and brake inputs to correct the airplane's alignment, the airplane did not respond. The pilot then added power to help correct the veering, but the airplane departed the left side of the runway and impacted a runway/taxiway sign. A post-accident inspection of the tubular steel left gear leg revealed that it had partially failed along a corroded weld line, and had bent backwards from its normal position. Corrosion/rust was present on about one inch of the fracture face, and along a wider area of the interior wall of the gear leg adjacent to the fracture. The fracture itself continued around about 70 percent of the circumference of the tubular leg. ## Aircraft - Registration: [N118CK](https://openairdocs.org/deregistered/N118CK-2023-04-26), registration cancelled 2023-04-26, S/N 1275, built 1980 (OpenAirDocs) - Reported make and model: Kreps Thorp T-18-C (T-18-C) - Registry model: [Kreps Curtis D. THORP T-18](https://openairdocs.org/model/kreps-curtis-d-thorp-t-18) (registry code 89510F6) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 1275 - Airframe hours: 996 - Engines: Lycoming O-320-E2D 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: George L. Avans - Registered owner: Glavans Rev Trust - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, October 1, 2008, 996 hours before - Departed: SBA, Santa Barbara, CA - Destination: PSP, Palm Springs, CA - Airport: PSP, Palm Springs Intl, runway 13L, 4,952 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 65; injuries: none; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review May 6, 2007; seat: left; flight hours: 652 total, 421 in this make and model, 621 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °F - Observed at: PSP ## 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 20090228003669A](https://openairdocs.org/incident/20090228003669A), Feb 28, 2009: Kreps T18, Palm Springs, CA, Substantial damage. (-23) Inspected aircraft and found "a" frame weld at the left gear had failed due to corrosion and metal fatigue. Pilot had no control when left gear collapsed… 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.