What visual indicators suggest extensive repair is needed for LO materials due to corrosion?

The presence of bubbles and disbonds in low observable (LO) materials is a critical visual indicator suggesting extensive repair is necessary due to corrosion. When LO materials, such as those used in stealth aircraft, begin to corrode, the deterioration can manifest in various forms. Bubbles often indicate that corrosion is causing the material to separate from its base structure, which can lead to significant integrity issues. Disbonds, where the surface layer loses adhesion to underlying layers or substrates, are a direct consequence of corrosion and indicate that the protective elements have been compromised. This situation can weaken the structural stability of the aircraft and ultimately affect its performance.

Other visual indicators, while they might suggest issues, do not point as definitively towards extensive corrosion-related repair needs as bubbles and disbonds do. For instance, discoloration and shrinking could be symptomatic of various problems but aren’t as specific to corrosion as the formation of bubbles and disbonds. Smooth surface and clarity generally indicate that a material is intact, while fading and oxidation may suggest wear but do not explicitly denote structural integrity issues that require immediate repair. Thus, the presence of bubbles and disbonds is a compelling and specific indicator of corrosion that warrants attention in LO materials maintenance.