What does a plotted TCPA of 30 minutes mean?
Short answer
CPA is forecast 30 minutes after the latest plot if motion continues
TCPA uses along-track distance from the latest plot to CPA divided by relative speed. It remains conditional and must leave time for decision and verification. Revisit CPA and TCPA Worked Plot.
Quick check
What does a plotted TCPA of 30 minutes mean?