C-FIYA, a Boeing 767-300 aircraft operated by Air Canada rouge, was conducting flight ROU1947 from Lima/Jorge Chávez Intl, Perú (SPJC) to Toronto/Lester B. Person Intl, ON (CYYZ) with 9 crew members and 253 passengers on board. During cruise flight at FL320, approximately 260 nm North Northwest of SPJC, the cabin crew reported an odour in the cabin described as “dirty socks”. The odour was not detected in the cockpit, however the flight crew elected to return to SPJC and declared a PAN PAN. During the descent to SPJC, approximately 7 tons of fuel were jettisoned, and the aircraft landed overweight without further incident.
The operator’s maintenance is investigating the cause.