Air Canada flight #AC155 to Calgary declared an emergency and returned to Toronto on Saturday, July 6 2024.
The Airbus A330-300 (registration C-GHLM) departed the runway 23 at 19:26 EDT then headed to North-West and climbed to FL350 to Calgary.
But 25 minutes into the flight, an alarm triggered in the cockpit about cabine pressure forcing the crew for a rapid descent to FL100.
The pilots declared an emergency (squawk 7700) and contacted the tower requiring a quick return to Toronto.
The A330 held 10,000 ft altitude before the final descent to YYZ. It landed back to runway 23 a bit more than one hour after departure.
The plane taxiied without further incident to gate B37.
