Chillpill:
For example, why cannot test pilots in a 4 jet engined aircraft take off, shut down 2 engines, and then fly a controlled profile at various levels/locations etc in this dust cloud to gather data that can also be supported by a stripdown of the operating engines once back on the ground. IF the 'low levels' of volcanic dust did cause an in flight shutdown, the 2 remaining donks would be available for use once clear of the area.
You're on the back of the drag-curve Chill - already suggested on Saturday, but only BA is listening. Do a thread search for "two engines".