# NTSB LAX99LA227: Cessna 120, N2651N, Chino, CA, June 25, 1999 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 24, 1999, 18:08 local (Jun 25, 1999, 01:08 UTC) - Place: Chino, CA - Coordinates: 33.999576, -117.679924 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.9996&lon=-117.6799&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report August 14, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 46639 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX99LA227 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/46639/pdf - Page: https://openairdocs.org/ntsb/LAX99LA227 ## Probable cause A preexisting fatigue fracture of the right axle. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Gear collapsed, landing - roll - landing gear,axle - fatigue (cause) - landing gear,axle - fractured (cause) - ground loop/swerve - inadvertent ## Analysis On the landing rollout the airplane veered to the left. An attempt was made to correct the travel to the left; however, a turn was initiated and the right wheel broke free. The right landing gear axle dug into the ground, and the airplane ground looped after the right wing tip struck the runway. The right axle was examined and found to have preexisting multiple-origin fatigue fractures. ## Factual narrative On June 24, 1999, at 1808 hours Pacific daylight time, a Cessna 120, N2651N, ground looped and collapsed the right landing gear during a touch-and-go landing at the Chino, California, airport. The airplane, owned and operated by the student pilot under 14 CFR Part 91, sustained substantial damage. The pilot was not injured during the local area solo instructional flight. Visual meteorological conditions existed for the flight and no flight plan was filed. The flight had originated at the Chino airport at 1730. The pilot stated that on the landing rollout the airplane veered to the left. He applied right rudder, which did not correct the travel to the left. He engaged the right brake, which did not have an effect on the airplane's movement to the left. The pilot reported that he was unable to perform a go-around due to the airplane's direction of travel. He kept the airplane on the asphalt, with the wings level, and applied the brakes to stop the airplane. He stated that the airplane "executed a moderate 180 [degree] turn," and the right wheel broke free. The right landing gear spar dug into the asphalt and broke free, the airplane made a turn to the right and the right wing struck the ground. A Safety Board investigator examined the right main landing gear and noted the appearance of a crack in the right axle. The axle was sent to the Safety Board's metallurgical laboratory for examination. The examination revealed that the fracture was through the barrel near the mounting flange. A microscopic examination of the fracture faces showed a discolored crescent-shaped area consistent with a preexisting crack. A stereo microscopic examination revealed that the crescent region had fracture features typical of multiple origin fatigue cracking. The scanning electron microscope examinations on the mounting flange fracture revealed optical observations of fatigue and overstress. The examination revealed fatigue striations and ductile dimples respectively. It was also noted that a crack existed diametrically opposite of the fatigue crescent. It was also examined and found to have characteristics similar to the original fracture crescent. ## Aircraft - Registration: [N2651N](https://openairdocs.org/deregistered/N2651N-2015-05-08), registration cancelled 2015-05-08, S/N 12909, built 1947 (OpenAirDocs) - Reported make and model: Cessna 120 - Registry model: [Cessna 120](https://openairdocs.org/model/cessna-120) (registry code 2071402) (OpenAirDocs) - Registry engine: [Continental C85 series](https://openairdocs.org/engine/continental-c85-series) (registry code 17008, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 12909 - Airframe hours: 4236 - Engines: Continental O-85 85 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Michael J. Stokes - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 19, 1998, 19 hours before - Departed: CNO - Airport: CNO, Chino, runway 26R, 4,856 × 260 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 47; student; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 40 total, 40 in this make and model, 5 as pilot in command, 10 in the last 90 days, 9 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 250° at 12 knots - Visibility: 7 statute miles - Lowest ceiling: none - Temperature: 82 °F, dew point 55 °F - Altimeter: 29.00 inHg - Observed at: CNO ## 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 19990624007529A](https://openairdocs.org/incident/19990624007529A), Jun 24, 1999: Cessna 120, Chino, CA, Substantial damage. Acft ground looped on landing and sustained substantial damage. (.4)on the landing rollout the airplane veered to the left. An attempt was made to correct the… 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.