C-FDST, an Airbus 320-200 aircraft operated by Air Canada, was conducting flight ACA615 from Halifax/Stanfield Intl, NS (CYHZ) to Toronto/Lester B. Pearson Intl, ON (CYYZ). During cruise flight, the flight crew received an ECAM Yellow Hydraulic System loss of fluid indication. A PAN PAN was declared and the flight landed at CYYZ without further incident with ARFF standing by. The operator’s maintenance found a leaking seal on the Filter Clogging Indicator and proceeded to replace it in accordance with the Aircraft Maintenance Manual procedures.
A subsequent leak check found the system serviceable and the aircraft was returned to service.