An aircraft, like any other metal, is prone to corrosion. However, in the aviation industry, the problem is much more expensive and hard to deal with. For example, in Canada alone, corrosion in airplanes costs the industry millions of dollars every year. And although much time and money are spent in delaying the process, nature almost always prevails.
Usually, corrosion development depends on how old the plane is, what type of environment it is being stored in, and how often it is cleaned and maintained. Below, we discuss the corrosion process in detail and how it can be recognized, detected, and prevented in aircraft.
What Is Aircraft Corrosion?
Corrosion is one of the biggest enemies of the aviation industry and the culprit behind most serious aircraft accidents. It is nothing more than the rust of metal parts and is caused when foreign materials such as dust, oil, grease, water, cleaning solutions, battery acids, and more are left for an extended period on the aircraft's surface.
There are many forms of aircraft corrosion, but the most common type of decay occurs when aluminum parts of the airplane interact with water and create aluminum oxide. And since aircraft are primarily made of aluminum, it is not just the exterior aircraft skin that is vulnerable to aluminum decay. In fact, as the airframe contracts and expands in response to heat and cold, water can penetrate deeper into the aircraft causing corrosion at a larger scale, making the aircraft unfit for flight in just a few years.
Aluminum corrosion does not produce a reddish color like rust does on most metals. Instead, it first appears as a whitish or gray dulling or powdery deposit on the aluminum surface, which then progresses to severe pitting. Severe pitting eventually destroys the metal.
Corrosion can be detected visually. And the sooner it is caught, the better. Frequent and thorough inspections enable technicians to treat and remove decay before it can cause extensive damage. Before the inspection, however, the aircraft must be adequately cleaned. This allows the technician not to miss any signs of corroding metal hidden underneath dust or grease.
During daily and preflight inspections, all accessible areas of the aircraft are checked for any signs of damage. Visual aids such as light probes, angled mirrors, optical instruments, and more are used to examine areas that aren't visible to the naked eye.
In addition to daily inspections, technicians and aircraft welders perform annual and more detailed inspections where they go over every inch of the airframe, including areas that are generally not accessible during routine inspections.
Where To Look For Corrosion
Areas of the aircraft that are commonly damaged by corrosion include; wheel wells, landing gear, battery compartments, battery vent openings, propeller, frontal engine areas, and wing flaps. These areas are commonly prone to corrosion because they are exposed continuously to harsh, corrosion-producing elements from the environment. Corrosion can also easily occur on the aircrafts surface if its protective layer of paint has been damaged or removed.
Corrosion can badly impact the airworthiness of an aircraft and damage it beyond repair. Therefore, to protect it from corrosion, prevention is the key. To prevent corrosion, you can do the following;
- Store or park your aircraft in a low-humidity environment. This will help delay the effects of corrosion.
- Regularly clean your aircraft to remove dirt and other pollutants from the surface.
- If possible, place your aircraft inside a hanger.
- Ensure the aircraft's cabins and windows are properly covered and sealed to prevent moisture from going inside the fuselage.
If your aircraft already shows corrosion signs, the only way to fix it is to remove the corroding part. Minor damage can be repaired by repainting and applying primer and abrasives. However, severe cases of corrosion require replacement. In situations like these, it is best to seek the help of a professional aircraft welder.