On 12 April 2013, a Ryanair Boeing 737-800 took a climb clearance intended for another Ryanair aircraft on the same frequency. The aircraft for which the clearance was intended did not respond and the controller did not notice that the clearance readback had come from a different aircraft. Once the wrong aircraft began to climb, from FL360 to FL380, a TCAS RA to descend occurred due to traffic just transferred to a different frequency and at FL370. That traffic received a TCAS RA to climb. STCA was activated at the ATS Unit controlling both Ryanair aircraft.