Speed change report to ATC
 

In US, not knowing the regulation in other countries, pilots are requested to report to ATC if their speed changes by TAS 10kt or 5%, whichever greater, per FAR.

I think there are many situation to change TAS, ex. turbulence, climb, descend, even air temperature change.
I do not image an aircraft climbs at the filed TAS.
Then especially in small planes, pilots need to use the analog flight computer to calculate TAS.

But I have not heard this kind of reports.
Do pilots have to report in any environment? even with radar contact?


If I misunderstand or overlook some exception for this regulation, please let me know.

Thank you.

Not very often reported unless under Mach number technique. On radar control the ATCO sees separation and the report is required but rather redundant.

GF

During climb your TAS is constantly increasing. ATC doesn't need a call every 5000 feet saying now we're going 270 knots, now we're going 290 knots, now we're going 320. The reg is average speed. At cruise that would be a change of 20+ knots. If the speed is just bouncing around your average isn't changing. If the turbulence is bad and you pull the power back to slow down 30 knots, then you should advise ATC.

Thank you for posts.

If pilots are approved for level change, are they still expected to climb or descend within TAS10knots or +/-5% without speed change report? Or the rules are only applied to level flight?

Then when the mandatory speed change report is exempt?
Many arrival route (STAR) have speed restriction but I've not heard the speed change report.

This is for Australia but I'd be surprised if the US was significantly different for this one.

Speed change report is required if you cruise speed changes from your flight planned cruise speed, that's it. Speed change reports during climb and descent are not required.

So, what´s the trigger, 5 % and 3 minutes?

AIM 5-3-3:

"Change in the average true airspeed (at cruising altitude) when it varies by 5 percent or 10 knots (whichever is greater) from that filed in the flight plan."

Thanks for the reference.
Appreciate it