FAA Powerplant Written Practice Test

What action should be taken to prevent moisture buildup in stored engines?

1. Keep the engine in a heated environment

2. Remove spark plugs and install dehydrator plugs

3. Store engines in air-tight containers only

4. Use dehumidifiers in the storage area

The correct answer is: Remove spark plugs and install dehydrator plugs

Removing spark plugs and installing dehydrator plugs is an effective method for preventing moisture buildup in stored engines. When engines are stored for extended periods, they can be susceptible to corrosion and damage from moisture that may accumulate inside the engine cylinders. By removing the spark plugs, one allows for airflow into and out of the combustion chamber, which helps equalize moisture levels. The installation of dehydrator plugs, which often contain desiccants, actively absorbs any moisture that could lead to corrosion. This creates a protective environment within the engine, minimizing the risk of rust and other moisture-related issues. Other options presented may contribute to moisture control but do not specifically target the interior of the engine in the same way. For instance, keeping the engine in a heated environment might help reduce humidity, but it does not directly alleviate the moisture problem inside the engine. Using air-tight containers can restrict airflow, but without the moisture-absorbing action of dehydrator plugs, they may not be sufficient on their own. Utilizing dehumidifiers in the storage area can help maintain a lower humidity level, yet this preventative measure doesn’t address moisture that may already be present within the engine itself as effectively as dehydrator plugs do.