Sorting out the causes for UAS glitches is becoming a top priority. According to a report by Defense Systems' Sean Gallagher, the mishaps have been uncomfortably recent and closely spaced. One involved the crash of an Army RQ-7B Shadow into the Mosul office of the Iraqi Islamic Party. A few weeks before that, a Predator crashed in central Iraq, and on September 13, the Air Force had to shoot down one of its Reapers.
The interesting part of the DS story pertains to the different ways that the Army and the Air Force handle the landings of the Predator UAS. Both fly a variant of the same basic design, but the Army prefers a software-automated landing as opposed to remotely piloted landings. More on this another time at the Glitch Reporter.