Narrative:

While on the localizer going into ZZZ; we had broken out of the clouds approximately 20 seconds earlier into VMC. While established on the localizer we received a TCAS alert to traffic below us by 200 feet. I leveled the aircraft and arrested my descent. Both myself and the first officer scanned for traffic and made visual contact a few seconds after the alert. The black helicopter (like a bell jetranger) was at our 1 o'clock position; moving to our 12 o'clock position and within 100 feet vertically. I took evasive action by banking to the right and climbing. I queried the tower as to how dangerously close he was to our approach. Their reply was that he was instructed to stay north of our final at all times and wasn't in radio contact with the tower. The helicopter then got on frequency and said that he had us in sight and was maintaining visual separation.if we had been in IMC the outcome could have been very grave. Additionally; whether the tower was in contact with the helicopter or not; it would have been helpful to have the traffic pointed out to us. Example: 'helicopter traffic at your 1 o'clock and will remain north of your final; and we aren't talking to him.'

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Original NASA ASRS Text

Title: PC-12 Captain reported a NMAC with a helicopter while on short final that had not been called out by ATC.

Narrative: While on the localizer going into ZZZ; we had broken out of the clouds approximately 20 seconds earlier into VMC. While established on the localizer we received a TCAS alert to traffic below us by 200 feet. I leveled the aircraft and arrested my descent. Both myself and the First Officer scanned for traffic and made visual contact a few seconds after the alert. The black helicopter (like a Bell JetRanger) was at our 1 o'clock position; moving to our 12 o'clock position and within 100 feet vertically. I took evasive action by banking to the right and climbing. I queried the Tower as to how dangerously close he was to our approach. Their reply was that he was instructed to stay north of our final at all times and wasn't in radio contact with the Tower. The helicopter then got on frequency and said that he had us in sight and was maintaining visual separation.If we had been in IMC the outcome could have been very grave. Additionally; whether the Tower was in contact with the helicopter or not; it would have been helpful to have the traffic pointed out to us. Example: 'Helicopter traffic at your 1 o'clock and will remain north of your final; and we aren't talking to him.'

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.