This is a new bug we just found:
http://aurora2.pentarch.org/index.php?topic=11565.msg140468#msg140468Basically, maintenance failure roll cannot distinguish components that are already destroyed and the components that cannot fail (such as hangers, fuel tanks), and after 20 such failed rolls, the ship explodes.
This is extremely unlikely for regular ships where most of their components can have maint failure. But for large barge carriers that are mostly hangers, or military tankers/MSP supply ships/colliers (yes, surprisingly, magazines do not have maint failures), it can happen with a not insignificant chance.
Basically, 80% of the ship are hangers -> 1.15% chance of explosion each time maint failure is rolled
90% -> 12.16% chance
93% -> 23.42% chance
95% -> 35.85% chance