Strange ID 053977 NATO02 around Eindhoven NL

Anyone have any idea what type plane this is and why the circling?
The only reference I cound find was to a DC-3 which will not reach 384 knots…
Zooming in shows at least 11 near perfect circles around Eindhoven before heading to Germany and near Geilenkirchen switching to NATO40 and disappearing at 7.000ft.

That is odd. But I have found out here that ICAO 053977 is an E-6B with registration 164406.

Some times there are two :slight_smile: