[F4U-1_Corsair]

well, I know they came with the stock game, but I think they only work on some aircraft that had them programmed.

FailedHydro: I know I have had my gear fail to lower on most planes,
FailedPneumo: flaps I beleive, when you jam them
FailedAmmoDetonates: I've only had this happen to me on the TB3, but sense I've started flying bombers again, I've mostly been using supressed hud messages, so it could account for when your plane just goes poof! from a single flack hit

FailedTank: maybe when a fuel tank is hit and drains out? not sure though
FailedRadiator: never had this said in the hud, but it would explain when you take a hit and your oil temp shoots up
FailedCompressor: perhaps this is when your engine runs away, don't think that would be realistic though if thats true.