Narrative:

The first officer was flying. Shortly after being handed off to departure control we were cleared to FL200. Through approximately 5000 ft we were IMC. Shortly thereafter we received a yellow TCAS alert. The screen indicated a target at our altitude and just off our left side (less than a half mi). I had the first officer turn right 30 degrees. We then received a red TCAS alert. Same target. I asked departure control if he had any known traffic in our airspace. At the same time we received a descent command from the TCAS. The first officer stopped the climb. Departure control said that there was no traffic in our area. All that was nearby was a target at our 11:30 O'clock position and 10 mi converging. Departure asked our heading. I responded we were heading 230 degrees. Departure told us to turn left to a heading of 180 degrees for the traffic. As we were making the turn; I had the first officer pull and reset the TCAS circuit breaker. Doing this canceled the TCAS alerts. I performed a self test which was normal. We continued the trip without further incident. We could think of no valid reason for the alerts. Upon returning I checked with maintenance to see if they had any suggestions for the alerts. The avionics tech said that he had only heard of it happening once before. It was shortly after the crew entered IMC just as we had. But he did not have any explanation; but he would do some research and get back to me.

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Original NASA ASRS Text

Title: ACR CAPT REPORTS PHANTOM TCAS ALERT AND RA WHILE CLIMBING OUT. ATC REPORTS NO TRAFFIC IN THE VICINITY. CIRCUIT BREAKER RESET ELIMINATES PROBLEM.

Narrative: THE FO WAS FLYING. SHORTLY AFTER BEING HANDED OFF TO DEP CTL WE WERE CLRED TO FL200. THROUGH APPROX 5000 FT WE WERE IMC. SHORTLY THEREAFTER WE RECEIVED A YELLOW TCAS ALERT. THE SCREEN INDICATED A TARGET AT OUR ALT AND JUST OFF OUR L SIDE (LESS THAN A HALF MI). I HAD THE FO TURN R 30 DEGS. WE THEN RECEIVED A RED TCAS ALERT. SAME TARGET. I ASKED DEP CTL IF HE HAD ANY KNOWN TFC IN OUR AIRSPACE. AT THE SAME TIME WE RECEIVED A DSCNT COMMAND FROM THE TCAS. THE FO STOPPED THE CLB. DEP CTL SAID THAT THERE WAS NO TFC IN OUR AREA. ALL THAT WAS NEARBY WAS A TARGET AT OUR 11:30 O'CLOCK POS AND 10 MI CONVERGING. DEP ASKED OUR HDG. I RESPONDED WE WERE HDG 230 DEGS. DEP TOLD US TO TURN L TO A HDG OF 180 DEGS FOR THE TFC. AS WE WERE MAKING THE TURN; I HAD THE FO PULL AND RESET THE TCAS CIRCUIT BREAKER. DOING THIS CANCELED THE TCAS ALERTS. I PERFORMED A SELF TEST WHICH WAS NORMAL. WE CONTINUED THE TRIP WITHOUT FURTHER INCIDENT. WE COULD THINK OF NO VALID REASON FOR THE ALERTS. UPON RETURNING I CHKED WITH MAINT TO SEE IF THEY HAD ANY SUGGESTIONS FOR THE ALERTS. THE AVIONICS TECH SAID THAT HE HAD ONLY HEARD OF IT HAPPENING ONCE BEFORE. IT WAS SHORTLY AFTER THE CREW ENTERED IMC JUST AS WE HAD. BUT HE DID NOT HAVE ANY EXPLANATION; BUT HE WOULD DO SOME RESEARCH AND GET BACK TO ME.

Data retrieved from NASA's ASRS site as of May 2009 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.