Avherald concedes in its report that the identity of the A380 operator is unconfirmed, and may not have been Emirates at all.
That theory is based on their interpretation of ADS-B data which, based on past experience of such analyses by AH, doesn't inspire a great deal of confidence.
Do you think you might be missing the point, Dave?
So the aircraft were flying apart and 1 - 2 minutes later the Challenger was rolled by the wake. That must be 20 - 30 miles behind the 380 and a thousand feet below it the wake was strong enough to roll a bizjet. For those offsetting a couple of miles to avoid wake that may well not be enough with these kinds of figures.
Wake vortices will generally descend at around 2 m/s or 300-500fpm depending on who you ask. They will persist much longer in still air conditions and, as is apparent from this report, conditions of little crosswind (the report states that winds were strong and north-westerly, i.e. directly behind the A380). All things being equal, offsetting by as little as a mile
should be enough to avoid wake in more-or-less any conditions. But is this common enough practice?
The real concern to me is that it has taken two months for this occurrence to be made public, when there could be valuable lessons to learn. Whilst avherald might boldly state that global ATC has been instructed to exercise particular care around A380s, my own ANSP has (at time of writing) offered little in the way of firm guidance.
LTP