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Hidden Corrosion Under Aircraft Paint

August 2019

Waiting to perform an aircraft paint job can be a major decision based on the immediate budget of flight departments, but waiting too long can have major consequences. Although the paint looks good and is not bubbling, corrosion may be forming just below the surface. Corrosion caught in the early stages is much easier to treat. If you wait too long between paint jobs, the money that you “saved” might have to be spent on the engineering and labor costs required to repair corrosion.

At Duncan Aviation, it has been our experience after stripping an aircraft to find spots of corrosion that have gone virtually undetected. Because of this, we pay close attention to key areas more prone to corrosion. The area around the static wick is a good example of where moisture is able to creep in where the paint cracks along the base and causes minor corrosion. This only becomes an issue with the next major inspection when they fail the resistance check. At that time, the bases are removed and the severity of the corrosion is determined. It is not unusual to have a patch repair or skin change on a flight control, which gets rather expensive and increases downtime.

If it hasn’t been that long ago when your aircraft was painted, the cracked paint can be reapplied and hopefully alleviate the situation. Although you can never fully prevent the corrosion, you can help to control it. Depending on the make/model aircraft that you operate, there may be other areas of corrosion concern.

Attention Cessna Operators

For Cessna operators, refer to Cessna CIL99-01 for further information on corrosion prevention and control on all of the Citation models. This CIL applies to the landing gear/wheel wells, flap wells and stabilizer aft spars and can be done in conjunction with paint to maximize the protection of the aircraft as well as provide the best access to apply the materials.