Dec 11 coming off an Intl flight connecting to YVR-YUL AC304 9:20am was scheduled to use a FIN that had been sitting in YVR for 48 hours and had a cancelled flight already. Obviously something was wrong with the plane and they thought they had fixed it. But then they announced a delay, followed by a longer delay to 4pm(!), followed by a cancellation -- due to an "unexpected maintenance issue" with a new flight at ... 4pm. I'm not sure how that's a "cancellation" and not just a new equipment or how that affects the compensation due or not...

So clearly they thought they had fixed some problem with the plane and just ... hadn't. That doesn't sound very "unexpected" to me. It just sounds like they failed to successfully maintain their equipment. But I'm sure AC would call it a "safety" issue to fly with a plane that needs maintenance. Is this going to be an easy APPR case or are they going to be stubborn about it?