I'm traveling YOW-YYZ-MEX today on AC439 and AC991.

AC439 was supposed to depart at 05:35 but is delayed until 06:00 (currently per the app, but realistically, we're not pushing back until 06:30 at best) due to crew shortage. Some kind of substitution happened this morning requiring them to slot in 1 flight attendant arriving from YVR on AC348, which is scheduled to get here at 05:53, and they can't start boarding AC439 until she's onboard AC439.

My connection to AC991 is looking dicey. Yet another AC OTP failure. Not happy about this.