Source: Simon Hradecky | www.avherald.com

An Air Canada Boeing 777-300, registration C-FNNU performing flight AC-891 from Rome Fiumicino (Italy) to Toronto,ON (Canada) with 448 passengers and 15 crew, was climbing out of Fiumicino’s runway 16R when the crew stopped the climb at FL080 due to a cargo smoke indication, cabin crew reported a chemical odour on board in addition. The crew declared Mayday, entered a hold and returned to Fiumicino for a safe landing on runway 16R about 45 minutes after departure. Responding emergency services did not find any trace of fire, heat or smoke or source of the odour.

The passengers were taken to hotels – a number of passengers complaining their bus took them to a hotel but told them, it was not their hotel and abandoned them – over night.

The occurrence aircraft remained on the ground in Rome for about 25 hours, then departed again and reached Toronto with a delay of about 26 hours.

On Nov 5th 2019 the Canadian TSB reported following the cargo smoke/fire indication and the cabin crew reporting a chemical odour in the cabin the crew declared Mayday and returned to Rome for an overweight landing. Maintenance personnel were unable to find any fault and returned the aircraft to service. After the aircraft departed again cabin crew again noticed an odour and determined the origin of that odour was the galley area heater. The flight was continued to Toronto for a safe landing. After landing in Toronto maintenance personnel found a faulty smoke detector and identified the door heater had been installed incorrectly with the airflow in the opposite direction.