Intersky DH8C at Zurich on Mar 16th 2014, unsafe gear

An Intersky de Havilland Dash 8-300, registration OE-LSB performing flight 3L-133 from Graz (Austria) to Zurich (Switzerland), was on approach to Zurich's runway 14 when the crew initiated a go around reporting technical reasons. The crew subsequently indicated that had an "unclosed door" indication on the right hand main gear and entered a hold to run the checklists, ATC switched to German then crew clarified they were having an unsafe gear indication with both green and red lights illuminated for the right hand main gear and didn't know whether the right hand main gear was locked or not. There was a possibility they needed to evacuate on the runway, emergency services were requested on stand by. ATC offered a fly by, the crew responded they had already visually checked from the cabin, gear was down but still unsure whether it had been locked into the down position. The crew positioned for another approach to runway 14, landed safely and reported after landing that everything was okay, the aircraft taxied to the apron.