Jazz DH8D near Toronto on Sep 24th 2014, loss of cabin pressure

A Jazz de Havilland Dash 8-400, registration C-GGMN performing flight QK-8533 from Toronto,ON to Thunder Bay,ON (Canada) with 32 people on board, was enroute at FL240 about 90nm northwest of Toronto when the crew received a cabin pressure warning and performed an emergency descent to 4000 feet. The aircraft returned to Toronto for a safe landing on runway 05 about 40 minutes later.

The Canadian TSB reported that maintenance suspected the cargo aft door seal may have been the problem, the seal was cleaned, repaired, lubricated and the aircraft passed a pressurization test.