FAA AMT (Aviation Maintenance Technician) Airframe Practice Exam

Why should a chemical rain repellant not be used on a dry windshield?

1. It can damage the windshield

2. It will restrict visibility

3. It is ineffective

4. It is too costly

The correct answer is: It will restrict visibility

Using a chemical rain repellant on a dry windshield can lead to restricted visibility. The purpose of a rain repellant is to help water bead and roll off the windshield during rainy conditions, improving visibility for the pilot. Applying the repellant on a dry windshield can cause the solution to form streaks or haze, making it harder to see clearly through the windshield, thus negating its intended purpose. Therefore, it is important to only apply a rain repellant when the windshield is wet to ensure optimal performance. Options A, C, and D are incorrect: A. Using a rain repellant on a dry windshield typically will not damage the windshield itself; instead, it may cause visibility issues. C. A rain repellant is typically effective in improving visibility during rainy conditions when applied correctly. D. The cost of the rain repellant does not relate to the issue of applying it to a dry windshield.