If the runway is blocked/obstructed, you can't use it - it's as simple as that. Those aircraft will have to go somewhere else!
What should happen is that the airport operator (generally referred to as the "aerodrome authority" in such discussions) will take steps to remove the wreckage and get the runway back into service. They have limited powers - in situations where it is vital that the runway be re-opened - to investigate incidents and commence recovery operations without waiting for AAIB to arrive.
Bear in mind in all these interviews that all they are looking for is that you keep your head under pressure, and are capable of thinking things through in a logical manner (even if you've never seen a particular situation before). As long as your answer makes sense and nobody dies, you'll be fine - keep cool!
Another question that often pops up on interviews is this:
An aircraft has run off the end of the runway and crashed, but the runway itself has been inspected and is serviceable. The wind is calm, and you've a backlog of traffic waiting to depart. What would you do?
[ 27 January 2002: Message edited by: 1261 ]</p>