On 29 May 2012, a British Airways Airbus A320 departing Zurich and in accordance with its SID in a climbing turn received and promptly and correctly actioned a TCAS RA 'CLIMB'. The conflict which caused this was with an AW 139 also departing Zurich IFR in accordance with a SID but, as this aircraft was only equipped with a TAS to TCAS 1 standard, the crew independently determined from their TA that they should descend and did so. The conflict, in Class 'C' airspace, was attributed to inappropriate clearance issue by the TWR controller and their inappropriate separation monitoring thereafter.