Originally Posted by
NumptyAussie
Is this feasible for a civilian drone...
I wouldn't try it with my "common or garden" widely available hobby done, for legal and common sense reasons, but given it's fairly sporty initial ROC and battery life I'd suspect it's possible, and certainly possible with something more bespoke.
As Kelvin has pointed out, probably the bigger mystery is the horizontal position..the lat/long given in the Airprox report puts the device over the North Sea, about 10 miles southeast of Clacton on Sea...