What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-5) This incident involved the question of TCAS ii operation. The aircraft was under approach radar control, and the flight crew was advised of unknown traffic. The crew acknowledged the traffic on their TCAS, and requested a vector for avoidance. ATC provided the requested vector however, the pilot responded to a ra alert to climb, which caused the loss of ATC required IFR separation from another IFR aircraft. This incident would not have occurred had the crew switched the TCAS from ra to ta as the aircraft entered the approach phase of the flight.
As the FAA filed it
(-5) THIS INCIDENT INVOLVED THE QUESTION OF TCAS II OPERATION. THE AIRCRAFT WAS UNDER APPROACH RADAR CONTROL, AND THE FLIGHT CREW WAS ADVISED OF UNKNOWN TRAFFIC. THE CREW ACKNOWLEDGED THE TRAFFIC ON THEIR TCAS, AND REQUESTED A VECTOR FOR AVOIDANCE. ATC PROVIDED THE REQUESTED VECTOR HOWEVER, THE PILOT RESPONDED TO A RA ALERT TO CLIMB, WHICH CAUSED THE LOSS OF ATC REQUIRED IFR SEPARATION FROM ANOTHER IFR AIRCRAFT. THIS INCIDENT WOULD NOT HAVE OCCURRED HAD THE CREW SWITCHED THE TCAS FROM RA TO TA AS THE AIRCRAFT ENTERED THE APPROACH PHASE OF THE FLIGHT.