Why is trial planning accuracy considered to degrade over time?

• A. Because memory fades.
• B. Because traffic situations are fluid and can change substantially in a short time.
• C. Because charts update only monthly.
• D. Because system time stamps drift.

Answer: (B)

Planning accuracy degrades over time because the operating environment is dynamic and uncertain. In air traffic planning, many factors—such as arrivals and departures, routing choices, weather, weather-related disruptions, incidents, and sector or equipment constraints—can change substantially in a short period. The plan is built on conditions observed or forecast at the planning moment, and as time extends, the number of unknowns grows and the likelihood that those initial assumptions will hold decreases. That increasing uncertainty means the earlier plan can become less accurate, so updates with fresh data and rolling re-optimization are essential. The other factors—memory fading, charts updating only monthly, or clock drift—do not drive the fundamental loss of accuracy; the core is how quickly conditions can change in a dynamic traffic environment.