The Aviation Herald reports this as an “Accident” of a Brussels Airbus A330-200 near Toronto on November 28th, 2017.
A Brussels Airlines Airbus A330-200, registration OO-SFZ performing flight SN552 from Toronto Pearson to Brussels with 251 passengers and 10 crew, was climbing out of Toronto shortly after takeoff when a number of passengers and cabin crew located in the aft cabin began to feel unwell, although no odour, fumes or visible smoke were detected.
The cabin crew reseated the affected passengers into the forward cabin, while the affected cabin crew were administered oxygen and recovered. The flight continued to Brussels for a safe landing. Medical services awaited the aircraft and examined the affected passengers and crew.
The affected cabin crew reported they suffered from nausea, palpitations, headache and abnormal blood pressure, and they felt a metallic taste.
The Aviation Herald learned of the occurrence on Nov 30th, 2017 and contacted the airline, which responded on Dec 4th, 2017 that 5 passengers and 4 cabin crew in the aft cabin (where only a few seat rows were affected) felt unwell shortly after departure, as if there was lack of fresh air; no (oil) smell or fumes were present in the cabin. Cabin crew reseated the passengers in those seat rows in the front of the cabin, where no such airflow issue existed. The passengers recovered. The cabin airflow rate was increased as well.
A doctor examined the affected persons after arrival in Brussels, and all passengers continued their journeys. The crew were sent to an aviation medical service for examination, where tests were conducted.
The aircraft was examined with the involvement of Airbus, and it was concluded the lack of airflow was probably the result of a temperature sensor in the cabin that malfunctioned due to dust in its surrounding (air supply filters). Due to the wrong measurement as result of the dust, the sensor instructed the air conditioning system to reduce the airflow. There had been a similar occurrence in another (non-Brussels Airlines) aircraft before.
The occurrence aircraft OO-SFZ remained on the ground for 31 hours, then returned to service.
Source: The Aviation Herald: http://avherald.com/h?article=4b1e618a&opt=0