NTSB Investigations of High-Strength Steel Landing Gear Components Fracturing from Fatigue Caused by Excessive Grinding
NTSB Investigations of High-Strength Steel Landing Gear Components Fracturing from Fatigue Caused by Excessive Grinding
Monday, October 20, 2025: 2:00 PM
The National Transportation Safety Board is an independent federal agency investigating transportation accidents across aircraft, rail, pipeline, marine, highway, and hazardous materials modes. Among these events, the agency has investigated multiple accidents involving fractures of landing gear components during landing. In these cases, the failed components exhibited fatigue thumbnail cracks on the fracture surfaces, initiating at the surface. These investigations discovered that the crack initiation sites coincided with areas displaying marks consistent with excessive heating. These marks, or ‘burns’, developed during grinding operations from rework of the parts. This presentation will detail how fatigue cracks initiate at these areas of excessive grinding, the fracture morphologies observed, and the diagnosis of the issue in an investigation. The presentation will also discuss safety improvements to prevent the fracture sequence from reoccurring, as well as the challenges of finding areas of excessive grinding and heat inputs to high-strength steel parts during rehabilitation.