Originally Posted by
fairviewroad
Do maintenance problems count? I've always thought of "Irrops" as referring to widespread problems...a blizzard, ATC issues, etc. An isolated mechanical delay/cancellation, while inconvenient, does not really strike me as rising to the level of "irrops". A single cancellation is much different than an entire hub suffering from 2+ hour delays (for example).
I consider anything outside of completing the flight within its scheduled timeframe (give or take a certain window) is an irrops. If mainetenance cancels your flight, it's most certainly an irrop in my book, as that was something that wasn't planned to occur by the airline at all and adversely affected the customer.