What is indicated in Block 17 on a flight strip?

Block 17 on a flight strip indicates the pilot's estimated time over fix (ETOF). This information is crucial for air traffic controllers as it helps them monitor the aircraft's progress along its route and ensure appropriate spacing between aircraft. By having the pilot's estimation, controllers can anticipate the aircraft's arrival at a specific point in its flight plan, allowing for better management of air traffic and enhanced safety.

This block is specifically dedicated to the pilot's prediction, as it reflects their calculations based on current flight conditions and intended speed. By comparing this estimate with actual times and the information contained in other blocks, controllers can make more informed decisions about air traffic flows and any necessary interventions.