Certified Flight Instructor - Flight Instructor Airplane Practice Exam

What is a key concern regarding the crankcase breather lines during cold weather preflight checks?

1. They can be clogged by ice from condensed vapors

2. They may leak oil during operation

3. They require lubrication to function properly

4. They can freeze in extremely low temperatures

The correct answer is: They can be clogged by ice from condensed vapors

The concern regarding the crankcase breather lines during cold weather preflight checks primarily revolves around the possibility of ice formation. When the temperatures drop, moisture in the air can condense inside the breather lines, particularly if they are not adequately heated or if the engine has not been sufficiently warmed up. This condensation can freeze, leading to blockages that prevent the crankcase from breathing properly. A blocked crankcase breather can result in increased internal pressure within the crankcase, which can cause serious engine damage or lead to oil leaks. It's crucial for pilots to ensure that these lines are clear of any obstructions before flight, especially in cold weather, making the assessment of possible ice blockage a vital part of the preflight inspection process. While oil leaks and lubrication are valid concerns, they are generally more relevant during other operational phases rather than specifically during cold weather checks. Similarly, while freezing temperatures can affect various components, the primary concern regarding the crankcase breather lines in cold weather conditions is the potential for ice blockage from condensed vapors.