Control Airframe Corrosion by Controlling Exposure to Water

November 2011

One word can strike terror in the heart of any DOM and Chief Pilot, especially during a large maintenance event: CORROSION. But that is the purpose of these events, finding and correcting any structural deficiencies.

Many airplanes operate in corrosive environments, but that does not always lead to a significant amount of corrosion found during inspections. The years of care leading up to that large maintenance event can be the predictor of the amount of corrosion found.

The key to controlling corrosion can be found in controlling water. There are several ways this is done. 

Water Control

• Keep the water out by maintaining good seals and sealing surfaces on the cabin doors and emergency exits.
• Keep the water in by regularly checking potable water and toilet systems for leaks.
• Get the water out quickly when a leak is found, because water likes to soak into and stay in carpet, carpet pads and insulation bags.

Protection of the Aluminum Structure

• Keep a good coat of paint on everything. A simple razor cut, a paint chip or an inadequate coat of paint is all water needs to start the corrosion process.
• Use the corrosion control procedures recommended by the manufacturer to augment that good coat of paint where needed and recoat if needed. On the CL604, Dinotrol is used to coat the top of the saddle tanks and the cabin floor support structure.

Keep on a good coat of grease

• Regular lubrication of the landing gear is great, but when the environment is harsh, an extra lubrication cycle is better.
• On the Challenger series and other models, grease is used on the fuel panels. If the panel is removed for any reason, the grease on the EMI gasket should be refreshed.

Finding corrosion during a major inspection is inevitable, but it doesn’t have to be detrimental. Taking the preventive steps now to control water, will lessen the likelihood of major structural damage in the future.