What action is required to prevent further deterioration of a CAT 4 item?

• A. Surface prep and touch up
• B. Replace the component
• C. Document the issue
• D. Do nothing until failure

Answer: (A)

Stopping further deterioration means restoring the protective barrier on the surface. For a CAT 4 item, the appropriate action is surface preparation and touch-up. This involves cleaning the area, removing any loose or active corrosion, feathering the edges, and applying primer and topcoat or other protective coatings to re-establish a continuous protective layer. When the coating is damaged but the base material is still sound, this repair halts corrosion progression and allows continued service.

Choosing to replace the component is reserved for cases where the damage is too extensive to repair with coating, or structural integrity is compromised. Merely documenting the issue doesn’t prevent corrosion from advancing, and doing nothing would let the deterioration proceed until a more serious failure occurs.