So here's a question; how resistant is an A-320 cockpit to a dropped cigarette? Back in the day when every Sky God (and half the passengers) smoked, presumably there were dropped cigarette ends all over the place; yet I don't know of cases where an aircraft was brought down by an ensuing fire. But is a relatively modern aircraft designed on the assumption that there will be no such dropped hot coals? Is there an ashtray provided in the cockpit, or do illicit smokers use a plastic cup with a bit of water in the bottom? If such an arrangement was balanced on the top of the cockpit coaming (where the fire/smoke warnings first appeared on the ACARS messages), and tipped or fell over, what would happen if water and a burning cigarette fell down the air-vents below the windshield?
We'll never know, I guess. Although the iPad/phone LiOn fire theory remains a prime suspect, it would be very interesting to hear answers to these questions from someone who knows the A320 flight deck and systems.
Dave - thanks for fixing the link. I cut-and-pasted the article because I suspected the link might not work, but thanks for tidying it up.