Light Transport; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP)
Confusion
ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Flight Crew Took Evasive Action
Human Factors
Aircraft was level at 10;000 feet flying direct to IDA. Approximately 20 miles East Southeast of the airport. ATC advised 'traffic at your 11 o'clock 9400 feet between you and the field maintain 10;000 crew checked TCAS display and began a visual scan. 3 targets spaced roughly 2 miles apart were observed on our display; but were not acquired visually. ATC advised she had 3 target who were not talking to her or IDA tower; and said we could climb or turn right. We maintained 10;000; and turned right approximately 30 degrees to clear the first target. The first target appeared to pass behind our aircraft on the TCAS display. The second target appeared to turn directly into the path of our aircraft and climb. Shortly after the second target appeared to turn; we were issued a 'traffic' TA; accompanied by yellow TCAS symbology; then an immediate RA to 'Climb; Climb.' The autopilot was disconnected and full power was applied. I pitched the aircraft into the green band indicated on the VSI. Within 1 or 2 seconds ATC advised that it appeared traffic was converging and suggested a climb. The PM advised ATC that we were climbing in accordance with an RA. We received a 'Clear of Conflict' message and leveled the aircraft at about 11;400 feet in roughly 30 seconds. ATC requested that we advise when clear; and the PM replied that we were clear and could return to 10;000 feet. The TCAS display was clear; so I began a slow descent back to 10;000 feet. We had the field visual acquired by then; and advised ATC; whereupon we were cleared for a visual approach. ATC inquired if we were able to identify an aircraft type on any of the targets. PM responded that we could not because we had never actually seen them. We took the handoff to IDA tower and had an uneventful landing.In this situation I'm not certain what additional steps could have been taken. The crew and ATC were both aware of the targets; but neither could predict the abrupt change in heading and altitude of the second target aircraft. As the PIC I could have requested a climb and turn to create a larger buffer between the target and my aircraft; however the turn appeared to initially accomplish a safe margin while allowing more space to descend once clear of the traffic. ATC could have issued a command to climb and turn to accomplish the same goal of separation between an IFR and VFR aircraft; however; I suspect that ATC felt that either option chosen by our aircraft would have provided the required separation; therefore issued the option rather than a command of clearance. There was no urgency or panic on the part of the crew or ATC; because all appeared adequate; and until the target aircraft changed course and altitude our separation would have been fine. In conclusion; I don't feel as though the crew or ATC 'missed' anything. I don't feel we incurred a loss of safe separation. I do feel that the predictive nature of our TCAS provided a safe resolution; that enhanced our separation and level of safety; and I'm very pleased to have this equipment.
Air taxi Captain reported multiple traffic conflicts while approaching the arrival airport IDA.