There can be multiple causes, but I will use my best judgement to select the MAIN cause. More specific wins, e.g. if it's a fuel problem due to human error, it will be judged as fuel problem, and "engine problem" wins over "technical malfunction".
Market closes when there is a report (even preliminary report) that without much doubt makes a conclusion on the main cause. If no such report exists after a year, I may extend the closing date.

I will not participate in this market.