Expressjet CRJ2 at Toronto on Jan 15th 2014, unsafe gear after departure

An Expressjet Canadair CRJ-200 on behalf of United, registration N835AS performing flight XE-5750/UA-5750 from Toronto,ON (Canada) to Washington Dulles,DC (USA) with 22 people on board, was climbing out of Toronto when the crew stopped the climb at 5000 feet reporting an unsafe gear indication. The aircraft returned to Toronto for a safe landing on runway 23 about 20 minutes after departure.

The Canadian TSB reported maintenance replaced a proximity sensor bracket and returned the aircraft to service.