Corrosion is a common yet costly issue for aircraft parts and components – and one that can cause major frustrations, safety risks, and expenses if not prepared against. Here is a breakdown of several different types of corrosion and some steps you can take to better identify and protect your aircraft against them.
What is corrosion?
Corrosion is a natural process in which metallic substances – such as the steel and aluminum most often used in aircraft manufacturing – decay gradually over time as a result of electrochemical or chemical reactions taking place on the metal’s surface or in the surrounding environment. In the case of aircraft operation, such reactions are occurring nonstop both inside the plane and in the high altitudes in which they travel.
Aircraft exhaust parts are particularly susceptible to corrosion and its effects due to their frequent exposure to extreme temperatures and rapid temperature changes that can lead to metal fatigue.
If left untreated, corrosion can lead to:
- Costly repairs
- Safety risks
- A loss of airworthiness for your aircraft
These threats are serious, and can lead to you being unable to fly your aircraft for as long as corrosion remains an issue.
It’s important to understand that corrosion is not entirely avoidable. It is an inevitable issue that must be planned against by learning to identify and take care of it when it does arise. Failure to do so can lead dangerous situations mid-flight.
Different types of corrosion
While corrosion is a common and inevitable issue for all aircraft, it can still be a challenge to spot and is not always easily visible right away. Here are some of the most common types of corrosion and their key characteristics.
Uniform surface corrosion
Uniform surface corrosion – also referred to as uniform etch corrosion or uniform attack corrosion – is the most common form of aircraft corrosion and primarily affects metal airframes. Uniform corrosion occurs at a fairly steady rate and can intensify when paint is stripped away from the body of the aircraft, directly exposing the underlying aluminum to the oxygen in the air. This causes an evenly distributed roughening of much of the metal surface of the plane – hence the term “uniform.” This form of corrosion may also reveal itself in the form of powdery deposits on the metal body of the aircraft.
Pitting corrosion most often affects alloys that come together to form protective oxide films, such as aluminum and magnesium. Pitting can pose a significant threat to metal propellors, as “pits” (small cavities in the metal) can form on the propellor blades or under de-icing boots as a result of trapped moisture, which can eventually damage to the blades. An early sign of pitting corrosion is a powdery gray or white material on the metal surface, that when brushed away reveals the small cavities underneath.
If a stainless steel or aluminum alloy’s structure lacks uniformity during the manufacturing process, its grain boundaries may fall victim to intergranular corrosion. This is one of the more difficult forms of corrosion to detect early on, but becomes more visible once exfoliation decay begins taking place at a more accelerated rate.
The aptly named stress corrosion impacts the parts of the aircraft that are under the most frequent and intense stress, such as the aircraft exhaust parts, engine crankshafts, and landing gear. As an aircraft ages, stress builds, and exposure to eroding conditions increases, so does the risk of stress corrosion. Over time, stress corrosion can lead to other side-effects like cracking of certain components – which can be deadly.
The risk and effects of stress corrosion may be reduced by:
- Performing stress relief heat treatments
- Applying protective coatings
- Utilizing corrosion inhibitors
Filiform corrosion is primarily a threat to metallic surfaces with a thin coat of organic film that are exposed to high humidity and acidic environments. While any such metals are at risk, the damage it causes tends to be most severe on aluminum, and if left untreated, filiform corrosion can also lead to intergranular corrosion over time.
Also referred to as concentration cell corrosion, crevice corrosion affects metal-to-metal joints and is most common in areas where moisture and other pollutants are trapped.
Tips to fight corrosion
As mentioned, corrosion of all types is impossible to prevent entirely for the lifetime of your aircraft – but there are steps you can take to delay the affects of corrosion, including:
- Keeping your aircraft in a low-humidity environment
- Storing your aircraft in a hangar or using cabin covers
- Sealing windows tightly to keep moisture out
- Washing your aircraft frequently to remove dirt and pollutants that can speed the development of corrosion
- Investing in higher-quality, more durable parts for your aircraft
Experience safe, durable, comfortable flight with Nicrocraft
When corrosion does occur, it needs to be treated one way or another before you return to the skies. Minor damage can be treated with abrasion, primers, or repainting, but more severe instances will require aircraft exhaust part replacement. And when replacement is the best option, it is best to do so with the highest-quality and most durable aircraft exhaust parts on the market.
Nicrocraft provides flight schools, FBOs, distributors, and aircraft owners with aircraft exhaust parts that are higher-quality and more durable than the competition – and we’ve been doing so for more than 50 years. All of our aircraft exhaust parts are built to the latest OEM specifications at our state-of-the-art facility in Oklahoma City.
We are a leading global supplier of exhaust parts for Piper, Cessna, Cirrus, Beechcraft, and more. We prioritize efficient communication and rapid turnaround to get you the parts you need, when you need them. We’re aviation people whose ultimate goal is to help you get in the air and stay there.