Narrative:

While conducting RNAV 19R; circle 01L at ccr during low visibility due to smoke; we noted traffic 100 feet higher than us but directly in our flight path. I was about to query ATC when they called out the traffic to me. I told ATC that we were likely to have a TCAS/RA and as soon as I said that; we got a 'traffic; traffic' followed by 'climb; increase climb' instruction. We immediately turned off the autopilot and began climbing; following the TCAS/RA climb instructions. We executed a missed approach and returned for another circling approach. During the second attempt; we encountered yet another aircraft 100' above us and again in our flight path. This time it was a helicopter that had drifted into the class D airspace. We did not get a TCAS alert but we had to wait until they were clear before making the base [turn] for the approach. I asked ground control what had happened and they offered no explanations. I called the tower chief and informed him of what took place. He was unaware of what transpired. We spoke to the captain of the first plane we encountered and he was pretty shaken up and said 'we were very close.' I never heard back from the tower [manager]. ATIS was reporting 7 miles with smoke but it was likely less than 3 miles. I told the tower [manager] this information and noted the beacon was turned on shortly thereafter (IFR). Ceiling was clear.

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Original NASA ASRS Text

Title: GA pilot reported a NMAC while on approach to CCR.

Narrative: While conducting RNAV 19R; circle 01L at CCR during low visibility due to smoke; we noted traffic 100 feet higher than us but directly in our flight path. I was about to query ATC when they called out the traffic to me. I told ATC that we were likely to have a TCAS/RA and as soon as I said that; we got a 'Traffic; Traffic' followed by 'Climb; Increase Climb' instruction. We immediately turned off the autopilot and began climbing; following the TCAS/RA climb instructions. We executed a missed approach and returned for another circling approach. During the second attempt; we encountered yet another aircraft 100' above us and again in our flight path. This time it was a helicopter that had drifted into the Class D airspace. We did not get a TCAS alert but we had to wait until they were clear before making the base [turn] for the approach. I asked Ground Control what had happened and they offered no explanations. I called the tower chief and informed him of what took place. He was unaware of what transpired. We spoke to the Captain of the first plane we encountered and he was pretty shaken up and said 'we were very close.' I never heard back from the Tower [Manager]. ATIS was reporting 7 miles with smoke but it was likely less than 3 miles. I told the Tower [Manager] this information and noted the beacon was turned on shortly thereafter (IFR). Ceiling was clear.

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.