Obviously the DA42 was flown from the UK to Afghanistan to calibrate the ILS.
Pretty unlikely... The FAA have a Challenger out here on a fairly regular basis to do that..
As I said earlier.. Mes has just recently had a whole new radar system installed..along with a new tower.. they're very proud of it...
It was most likely being used for calibrating that system.
Surveillance monitoring is carried out by altogether different types of aircraft both manned and unmanned.. The manned require a minimum crew and a range of equipment that the Twin Star could not possibly accommodate.