FAA Aircraft Dispatcher Practice Exam

Which type of structural ice is considered the most dangerous?

1. Clear ice due to its heavy and hard-to-remove nature

2. Rime ice because it is soft and easy to detect

3. Mixed ice as it melts quickly

4. Light ice because it can easily detach

The correct answer is: Clear ice due to its heavy and hard-to-remove nature

Clear ice is considered the most dangerous type of structural ice primarily because of its heavy and hard-to-remove characteristics. This ice forms when supercooled water droplets freeze upon contact with an aircraft surface, creating a smooth and transparent layer of ice that adheres strongly to the structure. The significant danger of clear ice lies in how it affects aircraft performance; it increases weight and alters the aerodynamic characteristics, leading to potential loss of lift and control. Additionally, clear ice is often difficult to detect visually, which can lead to late recognition of ice accumulation during flight, further compounding the risks to safety. In contrast, rime ice is softer and typically accumulates in a more irregular, frosted appearance that can make it easier to notice and often easier to remove. Mixed ice and light ice also present less danger, as their properties allow for quicker melting or easier detachment compared to the firmly adhering and dangerous nature of clear ice. Understanding these differences is crucial for pilots and dispatchers when assessing icing conditions and making operational decisions.