Casualties unknown

2000-04-21: Cessna 170A (N1233D) — St. Paul, MN

St. Paul, MN, US

On April 21, 2000, a Cessna 170A (registration N1233D) was involved in an aviation accident near St. Paul, MN. Investigators recorded the probable cause as: Hard landing on the left side, resulting in a broken left main landing gear axle. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

A student pilot's hard landing on the left side caused the left main landing gear axle to break, resulting in the left wingtip striking the runway. Post-incident inspection revealed a circumferential fracture at the axle flange except at a spot weld.

Incident Overview

During landing, a student pilot executed a hard touchdown on the airplane's left side. The impact caused the left main landing gear axle to fracture, subsequently allowing the left wingtip to contact the runway surface.

Examination Findings

Post-incident examination of the aircraft revealed that the left main landing gear axle had broken at the gear leg mounting flange. The fracture extended around the circumference of the axle, flush against the flange, with the exception of a 7/16-inch wide spot weld observed on one side of the axle where the fracture deviated outward. The left landing gear box was displaced inward and aft. No other anomalies were identified with the aircraft.

Maintenance History

The aircraft had undergone its annual inspection on March 9, 2000. Since that inspection, the airplane had accumulated 4 flight hours up to the time of the incident.

Manufacturer Guidance

According to the aircraft manufacturer, cracked landing gear axles should be replaced. The manufacturer provides no guidance or approval regarding performing welds on their landing gear axles. The presence of the spot weld on the fractured axle is noted, though its origin or approval is not addressed in the manufacturer's documentation.

Probable cause

Hard landing on the left side, resulting in a broken left main landing gear axle.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X20784. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.