I understood that the BA flight flew at 40,000 feet, which is well above the ash cloud which topped at 35,000feet ( I think), so is that a representative test? Or proof that an aircraft can climb and descend through an ash cloud and have no damage, as opposed to the BA flight in the 80's which flew through the ash cloud for a prolonged period of time.
I'm not sure what altitude the KLM,DLH and AFR flights were at.
Louby