When are you required to report airspeed changes to Center?

When are you required to report airspeed changes to Center?

• A. Greater than 5% change
• B. Greater than 10 knots change
• C. Greater than 5% or 10 knots change
• D. Never

Answer: (C)

The main idea here is that Center needs to be kept informed about meaningful changes in your airspeed so they can maintain proper separation and sequencing of traffic. You should report any airspeed change that exceeds five percent of your current speed or exceeds ten knots, whichever threshold you pass first. This dual rule works well across the speed range: at higher speeds, even a small percentage change matters; at lower speeds, a modest absolute change can be significant for spacing. For example, at 180 knots a change of more than about nine knots would exceed five percent and require reporting, and a change over ten knots would also trigger a report. If neither threshold is exceeded, you can stay on your previously assigned speed without informing Center.

The main idea here is that Center needs to be kept informed about meaningful changes in your airspeed so they can maintain proper separation and sequencing of traffic. You should report any airspeed change that exceeds five percent of your current speed or exceeds ten knots, whichever threshold you pass first. This dual rule works well across the speed range: at higher speeds, even a small percentage change matters; at lower speeds, a modest absolute change can be significant for spacing. For example, at 180 knots a change of more than about nine knots would exceed five percent and require reporting, and a change over ten knots would also trigger a report. If neither threshold is exceeded, you can stay on your previously assigned speed without informing Center.