Corrosion Control Extends Aircraft Lifespan

Much of the U.S. Air Force's aircraft fleet is decades old, which is why preventive maintenance is critical. A simple wash and paint touch-up can extend a jet's service life. Structural maintenance procedures for aircraft are conducted at Osan Air Base, South Korea 51.

Maintenance squadrons perform this work in corrosion control repair shops, also called "paint barns" by technicians. Using mechanical and chemical procedures, they identify, remove and treat corrosion.

Staff Sergeant Sameth Mao, responsible for corrosion control in the 5th Maintenance Squadron, explains: "Metals have a tendency to return to their natural state. Outdoor use and even time itself can accelerate the corrosion factor. Since an aircraft is also a man-made object, it will always corrode."

Corrosion is a natural process that causes refined metals to convert to more stable elements and compounds such as oxygen and hydroxide. Extended exposure to air initiates the process, so proper prevention requires a sealed advanced protective coating paint layer.

According to research conducted by Bio Water Synergistics, a company specializing in aircraft washing equipment for military aviation, maintenance costs related to corrosion can account for up to 80 percent of an aircraft's total maintenance expenses over its service life, making corrosion control procedures critically important.

Aircraft are washed every 90 days to remove all types of dirt, grime and oils generated during flight that could hide any nick or dent in the paint.

Senior Master Sergeant Alan Johnson, a maintenance specialist for aircraft fuselages, states: "Advanced protective coating is expected to last 10 years. According to Air Force regulations, aircraft are repainted every 10 years, but necessary touch-ups are performed frequently."

After aircraft complete the maintenance inspection phase, the paint coating is thoroughly examined for scratches and dents that may require touch-up. If any are found, the aircraft is sent to the corrosion repair shop for necessary painting.

Johnson said, "Once we determine which areas of the aircraft need painting, we begin masking, taping and covering all areas that should not be painted." He added, "After all areas are masked, we sand and smooth any gouged or nicked areas to ensure the finished product looks even."

Johnson continued, "After sanding is complete, we wipe the areas to be painted to remove all dust and debris, and once the areas are clean, we spray a light primer coat." "After the primer dries, the final coat is sprayed and then allowed to cure."

Mao stated that complete sanding, priming and painting of an aircraft from start to finish takes approximately five business days, followed by an additional 72 hours for the coating to cure properly.

For proper curing of the coating, the aircraft must be kept at temperatures between 15-30 degrees Celsius. After all preventive maintenance procedures are completed, the aircraft is considered mission-ready and returned to operational status.