http://avherald.com/h?article=43a46313

An Air Canada Embraer ERJ-175, registration C-FFYG performing flight AC-501 from Toronto,ON (Canada) to Chicago O'Hare,IL (USA) with 44 people on board, was in the initial climb out of runway 05 when the crew retracted the gear but received a "BRAKE CNTRL FAULT" ECAM message shortly followed by a "LANDING GEAR LEVER DISAGREE" warning. The tower reported seeing that the left hand main gear had not retracted. The crew levelled off at 5000 feet, actioned the relevant checklists, cycled the landing gear without success, declared PAN and returned to Toronto for a safe landing on runway 05 about 25 minutes after departure.