FAA Powerplant Written Practice Test

What is a critical step when preparing an engine for indefinite storage?

1. Running the engine at high speeds

2. Replacing the oil with a corrosion preventative mixture

3. Keeping the engine in a cold environment

4. Using standard oil for preservation

The correct answer is: Replacing the oil with a corrosion preventative mixture

When preparing an engine for indefinite storage, replacing the oil with a corrosion preventative mixture is a critical step because it effectively protects the internal components of the engine from moisture and contaminants that can lead to corrosion. During prolonged periods of inactivity, engines are susceptible to rust and other forms of degradation, particularly in humid environments. The corrosion preventative oil not only provides lubrication but also creates a barrier against moisture and air, which are primary factors in the oxidation process that leads to corrosion. This treatment is designed to inhibit rust formation and preserve the integrity of engine parts, ultimately extending the lifespan of the engine when it is brought back into service. Other methods, such as running the engine at high speeds or using standard oil for preservation, do not provide the same level of protection against corrosion during storage. Keeping the engine in a cold environment might help to some extent, but it does not address the need for proper lubrication and corrosion prevention. Therefore, the use of a corrosion preventative oil mixture is essential for maintaining engine health during extended periods of non-use.