Which of the following is NOT a procedure used to prevent corrosion?

Corrosion prevention is a critical aspect of aircraft maintenance, and various procedures are employed to mitigate the risk of corrosion forming on metal surfaces. Lubrication, sealing, and inspection are all integral practices in this context.

Lubrication serves to create a barrier between metal surfaces and moisture, which is a key factor in corrosion formation. It helps to reduce friction and wear as well, contributing to the longevity of the aircraft components.

Sealing involves applying protective coatings to surfaces to prevent exposure to the elements that might cause corrosion. This includes paints and other sealants designed to provide a durable shield.

Inspection is vital for detecting early signs of corrosion or damage, allowing for timely maintenance actions to prevent further deteriorative processes. Regular inspections can help ensure that any vulnerabilities to corrosion are addressed promptly.

On the other hand, scratching the surface does not prevent corrosion; rather, it can expose the underlying metal to environmental factors that promote corrosion. When the protective layer is compromised or scratched, the likelihood of corrosion occurring increases. This activity directly contradicts the practices aimed at corrosion prevention, making it the correct choice for identifying a procedure that does not prevent corrosion.