Corrosion is one of the most complex forms of damage to an aircraft and its components. When left unidentified and untreated, your airplane’s metallic corrosion can cause structural deterioration of your plane and its parts. Not only is this type of impairment increasingly costly to repair, but it can also result in significant safety risks and loss of airworthiness for your aircraft.
Corrosion is a natural process that involves the gradual decay of a metallic substance caused by electrochemical or chemical reactions to its surface and the surrounding environment. As aircraft erosion occurs rapidly, you need to understand how to detect or slow down this phenomenon. Before trying to correct this issue, you must first know about common corrosion types observed in aircrafts.
Uniform Surface Corrosion
Surface corrosion is the most common corrosion type that mainly affects metal airframes, resulting in the general fading of an exposed metallic surface. As the term suggests, uniform surface corrosion happens at an even rate, which causes the entire metal surface to appear rough and frosty.
This type of metallic decay occurs when aluminum gets directly exposed to oxygen present in the air. This process’s primary cause is when your aircrafts paint gets stripped away due to wear and tear, acidic or chemical fumes, increased humidity, or the presence of increased quantities of contaminants in the surrounding environment.
Pitting decay can be observed in any metallic surface, but it usually affects magnesium or aluminum alloys in particular. One of the early signs of this form of corrosion is the appearance of a powdery gray or white material on a metal surface. You can see the presence of small cavities on the metal surface after brushing away this substance.
When it comes to metal airplane propellers, pitting corrosion is an increasingly severe issue. These pits are often caused by trapped moisture, which can grow on the propeller blades or under inadequately installed de-ice boots. No matter how minor this problem seems, it could still significantly damage the propeller blades.
Any sign of pitting corrosion should be addressed by a certified aviation expert to save your aircrafts propellers.
Intergranular corrosion is a type of aircraft damage that affects an airplane’s stainless steel or aluminum alloy’s grain boundaries. It usually occurs due to the alloy structure’s lack of uniformity during the material’s manufacturing process.
This type of corrosion is highly challenging to detect, which is often only identified once it has already progressed to exfoliation decay, determined by the lifting of the metal surface. It’s also usually too late to save the affected metal piece at this stage of corrosion.
Stress corrosion usually harms your aircraft’s most stressed parts, like engine crankshafts or landing gears. The level of risk of this type of metallic decay increases with your plane’s age and increased exposure to eroding conditions. One of the side effects of stress corrosion is cracking, which can significantly increase the metal’s degradation rate.