Which statement about cathodic protection in aircraft structures is true?

Which statement about cathodic protection in aircraft structures is true?

• A. It makes the protected metal the cathode; uses sacrificial anodes; not commonly used for primary airframe structures; coatings and barrier protections are the main method
• B. It is a coating method
• C. It is a diagnostic test
• D. It is a painting technique

Answer: (A)

Cathodic protection works by making the metal to be protected act as the cathode, while a more anodic material (sacrificial anode) or an external power source provides electrons to prevent the metal from corroding. In aircraft structures, sacrificial anodes are not commonly used on the primary airframe because of practicality, weight, and maintenance concerns; the most important and widely used method to prevent corrosion on primary airframes is barrier protection—coatings, primers, sealants, and other barriers that keep moisture and ions from reaching the metal surface. Cathodic protection can be used in specific, limited cases, but it is not the typical primary method for airframes. It isn’t a coating, a diagnostic test, or a painting technique.

Cathodic protection works by making the metal to be protected act as the cathode, while a more anodic material (sacrificial anode) or an external power source provides electrons to prevent the metal from corroding. In aircraft structures, sacrificial anodes are not commonly used on the primary airframe because of practicality, weight, and maintenance concerns; the most important and widely used method to prevent corrosion on primary airframes is barrier protection—coatings, primers, sealants, and other barriers that keep moisture and ions from reaching the metal surface. Cathodic protection can be used in specific, limited cases, but it is not the typical primary method for airframes. It isn’t a coating, a diagnostic test, or a painting technique.