Instrument Rating Checkride Practice Test

What is the impact of frost on an aircraft's surfaces?

1. Decreases weight

2. Increases lift

3. Increases stall speed and reduces performance

4. Has no effect on performance

The correct answer is: Increases stall speed and reduces performance

The presence of frost on an aircraft's surfaces significantly affects its aerodynamic performance. When frost accumulates, it alters the airflow over the wings, leading to an increase in stall speed and a reduction in overall performance. The rough surface created by frost disrupts the smooth flow of air, which is essential for generating lift. This disruption can result in a stall occurring at a higher airspeed than normal, which is particularly dangerous during critical phases of flight such as takeoff and landing. Additionally, the extra roughness added by frost can disturb the lift generation capabilities of the wings, resulting in decreased efficiency during flight. Consequently, pilots must be vigilant about removing any frost or ice before flight to ensure optimal performance and safety.