FAA Powerplant Written Practice Test

What is always the final step when degreasing a metal engine part with a soap and water chemical solution?

1. Rinse with clean water

2. Dry the part completely

3. Respray the part with oil

4. Inspect for residue

The correct answer is: Respray the part with oil

The final step when degreasing a metal engine part with a soap and water solution focuses on ensuring that the part is properly prepared for further processing or reassembly. Ideal practice would involve inspecting for any remaining residues after washing, ensuring that the part is dried completely to prevent corrosion, and applying a protective oil if necessary. When using a soap and water solution, rinsing with clean water is crucial to remove any soap residue. Following this, drying the part completely is essential to eliminate moisture, which could lead to rust or other forms of corrosion. In some applications, it's standard to respray the surface with oil to provide a protective barrier against oxidation. However, this is not a universally mandated final step after degreasing. The correct procedure emphasizes the importance of these steps relative to the purpose of preparing the engine part for its next stage, be it inspection, shipping, or reinstallation. In practical terms, while applying oil can be effective, it typically would follow rather than replace the specific rinsing and drying processes intended to ensure a clean and ready surface.