Chugalug
I guess you win the prize and get to answer the 2 ultimate questions:
Bearing in mind that the AAIB was unable to find any fault that could have caused the crash:
Q1.
What exactly was the fault that caused the crash?
Bearing in mind that this tragedy has not been repeated in the 14 years 8 months and 10 days since the Mull Crash:
Q2.
What exactly was the Modification that cured the fault?