“It just snapped” is rarely the whole story. A component that fails in service has usually been failing for some time, and the photographs, the service history and the repair records often hold enough to say whether the failure claimed is the kind that happens, in that part, in that condition, under that load.
What a screening assessment covers
- The failure mode from the record. Whether the fracture, bend or corrosion shown in the photographs is consistent with fatigue, overload, corrosion or a combination, and whether the evidence supports the sequence claimed: did the part fail before the collision and cause it, or fail in the collision.
- Service and repair history. Whether the maintenance record, the mileage and any previous repair bear on the condition of the part, and whether the failure claimed is one the history would predict.
- Steering, column and linkage. The condition of the steering system as the record shows it, including loss of power assistance, and whether that condition could have produced the loss of control described.
Laboratory examination
Where a question turns on the fracture surface itself, fractography is arranged through an accredited laboratory and reported as such, with the laboratory’s findings presented as the laboratory’s and the engineering interpretation presented as mine. The report says who did what. A screening assessment from the record will often say that such an examination is necessary before any firm view can be given, and what it would cost; that is a useful answer in itself.
The limits
A photograph shows the surface a camera saw. It does not show the microstructure, the hardness or the residual stress, and a report from photographs says so. The same mechanics apply whether the part is a suspension arm, a steering linkage or a wheel bearing, and the methods page shows the fracture and corrosion checks working on published data.
