In corrosion maintenance for a CAT 4 item, which action is described as necessary to stop deterioration?

• A. Surface prep and touch up
• B. Replace component
• C. Record keeping only
• D. Diagnostics only

Answer: (A)

The key idea is that stopping corrosion requires removing the existing corrosion and restoring a protective barrier on the metal surface. Surface prep and touch up accomplish this by cleaning or removing rust and oxides, lightly abrading to create a good bonding surface, and applying primer and a protective coating to seal the metal again. This interruption of exposure to moisture and oxygen halts the ongoing chemical attack, stopping deterioration at its source.

Diagnostics or record keeping don’t address the material condition—they don’t remove corrosion or re-establish protection. Replacing the component might be necessary in cases of severe damage, but the action described as necessary to stop deterioration is the surface preparation and touch up, because it directly restores the protective layer and halts further corrosion.