Narrative:

During climb to 23000 ft near centralia VOR, while passing through approximately 14500 ft, the TCASII alerted us to traffic converging rapidly from about 2 O'clock position. It indicated the aircraft was 900 ft above us. I immediately instructed the first officer (who was flying) to 'stop the climb.' the TCASII went from 'traffic' to 'monitor vertical speed' to 'descend, descend' in rapid progression. This traffic was not reported by ATC. In response to the TCASII RA, the convergence rate and altitude closure, the first officer appropriately closed the throttles and pushed over. I asked ATC if they showed traffic to our right. ATC responded with what sounded like 'affirmative, VFR fifteen five.' I did not observe the final crossing altitude. We did not visually sight the aircraft. During the push over in response to the RA, 2 passenger were lifted from the floor while returning from a lavatory. No injuries occurred. I informed ATC 'we had a TCASII alert on that aircraft.' they responded 'roger.' I informed him 'we had to stop the climb and descend to avoid that traffic.' he responded 'roger' and gave us a frequency change. My impression was that the controller was as startled as we were. His responses were short and tight. Though I never saw the traffic, due to the closure rate and relatively high altitude I suspected it was possibly a military aircraft. Solution? Possibly better ATC vigilance. If it was a military aircraft better communications with ATC about altitude and intentions.

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Original NASA ASRS Text

Title: FLC OF AN MLG STOPPED THEIR CLB AND DSNDED IN RESPONSE TO A TCASII RA CAUSED BY A CONVERGING TARGET COMING AT THEM AS THEY CLBED. ATC ANSWERED AFFIRMATIVELY WHEN QUESTIONED BY THE CAPT REGARDING IF ATC KNEW OF THE INTRUDER ACFT.

Narrative: DURING CLB TO 23000 FT NEAR CENTRALIA VOR, WHILE PASSING THROUGH APPROX 14500 FT, THE TCASII ALERTED US TO TFC CONVERGING RAPIDLY FROM ABOUT 2 O'CLOCK POS. IT INDICATED THE ACFT WAS 900 FT ABOVE US. I IMMEDIATELY INSTRUCTED THE FO (WHO WAS FLYING) TO 'STOP THE CLB.' THE TCASII WENT FROM 'TFC' TO 'MONITOR VERT SPD' TO 'DSND, DSND' IN RAPID PROGRESSION. THIS TFC WAS NOT RPTED BY ATC. IN RESPONSE TO THE TCASII RA, THE CONVERGENCE RATE AND ALT CLOSURE, THE FO APPROPRIATELY CLOSED THE THROTTLES AND PUSHED OVER. I ASKED ATC IF THEY SHOWED TFC TO OUR R. ATC RESPONDED WITH WHAT SOUNDED LIKE 'AFFIRMATIVE, VFR FIFTEEN FIVE.' I DID NOT OBSERVE THE FINAL XING ALT. WE DID NOT VISUALLY SIGHT THE ACFT. DURING THE PUSH OVER IN RESPONSE TO THE RA, 2 PAX WERE LIFTED FROM THE FLOOR WHILE RETURNING FROM A LAVATORY. NO INJURIES OCCURRED. I INFORMED ATC 'WE HAD A TCASII ALERT ON THAT ACFT.' THEY RESPONDED 'ROGER.' I INFORMED HIM 'WE HAD TO STOP THE CLB AND DSND TO AVOID THAT TFC.' HE RESPONDED 'ROGER' AND GAVE US A FREQ CHANGE. MY IMPRESSION WAS THAT THE CTLR WAS AS STARTLED AS WE WERE. HIS RESPONSES WERE SHORT AND TIGHT. THOUGH I NEVER SAW THE TFC, DUE TO THE CLOSURE RATE AND RELATIVELY HIGH ALT I SUSPECTED IT WAS POSSIBLY A MIL ACFT. SOLUTION? POSSIBLY BETTER ATC VIGILANCE. IF IT WAS A MIL ACFT BETTER COMS WITH ATC ABOUT ALT AND INTENTIONS.

Data retrieved from NASA's ASRS site as of July 2007 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.