The Air XL A320 crash was caused by pilot error, nay gross stupidity.
The test schedule was VERY clear that the AOA sensor check MUST be conducted at or above 10,000 feet AGL. The damn fool (not a qualified test pilot) conducted the test at low level where the result of a failure was fatally predictable.
Every test can either pass or fail, that is why they are on the test schedule. The purpose of the test was to check that the AOA sensors were working correctly - the test failed.
DUH.