Which area is commonly checked for corrosion in aircraft skin assemblies?

Which area is commonly checked for corrosion in aircraft skin assemblies?

• A. Fuel tanks
• B. Seams and lap joints
• C. External skin
• D. Control surface recesses

Answer: (B)

Moisture and contaminants tend to collect in the crevices where skin panels meet—seams and lap joints. The overlap of panels, along with rivet lines and sealants, creates sheltered areas where water can pool and sealant can deteriorate, forming galvanic cells between metals. This environment makes corrosion start and propagate more readily at these joints than along smooth external skin, so inspectors routinely check them for signs like sealant failure, staining, or corrosion around rivets. While corrosion can appear in other areas, seams and lap joints are the most common and critical to inspect in skin assemblies.

Moisture and contaminants tend to collect in the crevices where skin panels meet—seams and lap joints. The overlap of panels, along with rivet lines and sealants, creates sheltered areas where water can pool and sealant can deteriorate, forming galvanic cells between metals. This environment makes corrosion start and propagate more readily at these joints than along smooth external skin, so inspectors routinely check them for signs like sealant failure, staining, or corrosion around rivets. While corrosion can appear in other areas, seams and lap joints are the most common and critical to inspect in skin assemblies.