Narrative:

In descent to mco approach control cleared us from 12000' to 9000'. After descending 100' the TCASII gave air traffic area audible 'traffic' call. Aircraft about 5 mi ahead 30' below at 11:30 O'clock. After descending about 300' TCAS gave a RA 'climb' command calling for a 1200-1500 FPM climb. We immediately initiated a climb. We climbed to 13000' at which time tcs no longer commanded a climb, but changed to a do not descend command on vsi. I sighted the intruding aircraft pass by and notified ATC of our action and the reason. ATC replied that the intruder was VFR and he had not seen it earlier. When we were clear we continued descent to 9000'. Supplemental information from acn 165438. Level at 12000'. Orlando approach cleared us to 9000'. Just pushed the autoplt buttons to initiate a descent, when we heard the call of traffic from the TCAS. I looked at the radar screen at 5 mi a yellow target showed up with an indication of 03 (300 below us). I remembered thinking why wasn't he pointed out to us and then thinking he must be going our way and wouldn't be a factor. At that point we got a RA (resolution advisory) of climb, climb. The first officer said it wants you to pull up. As I pulled up I look at the V/V it showed a red indication (red arc) for descent al the way to 1500 FPM climb. I never did see the green arc. The first officer said at first glance he didn't either but did see it later. Could have been the top of the instrument cut out the view of the green arc since the green arc is the furthest from the center of the instrument or it could be that the green arc is only 3 dots long nd doesn't stand out. I climbed at 1500 FPM or greater. We xed over the traffic. The readout showed him red directly under us and -10 (1000' below). The altimeter showed 12800'. The first officer spotted him just prior to us passing him. We told approach we were taking action to avoid traffic as indicated by the TCAS. Never saw the traffic. First officer did. Southwest red symbol directly under aircraft and 1000' below on radar screen. Don't know what I would have done if we had traffic above us and had gotten a second resolution advisory to not climb. Liked to think I would have leveled off and flown between them. Don't know.

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Original NASA ASRS Text

Title: MLG GOT DESCENT CLRNC FROM ATC, THEN RECEIVED A TCAS II ALERT AND CLIMBED 1000' WITHOUT CLRNC TO AVOID A VFR ACFT.

Narrative: IN DSNT TO MCO APCH CTL CLRED US FROM 12000' TO 9000'. AFTER DSNDING 100' THE TCASII GAVE ATA AUDIBLE 'TFC' CALL. ACFT ABOUT 5 MI AHEAD 30' BELOW AT 11:30 O'CLOCK. AFTER DSNDING ABOUT 300' TCAS GAVE A RA 'CLB' COMMAND CALLING FOR A 1200-1500 FPM CLB. WE IMMEDIATELY INITIATED A CLB. WE CLBED TO 13000' AT WHICH TIME TCS NO LONGER COMMANDED A CLB, BUT CHANGED TO A DO NOT DSND COMMAND ON VSI. I SIGHTED THE INTRUDING ACFT PASS BY AND NOTIFIED ATC OF OUR ACTION AND THE REASON. ATC REPLIED THAT THE INTRUDER WAS VFR AND HE HAD NOT SEEN IT EARLIER. WHEN WE WERE CLR WE CONTINUED DSNT TO 9000'. SUPPLEMENTAL INFO FROM ACN 165438. LEVEL AT 12000'. ORLANDO APCH CLRED US TO 9000'. JUST PUSHED THE AUTOPLT BUTTONS TO INITIATE A DSNT, WHEN WE HEARD THE CALL OF TFC FROM THE TCAS. I LOOKED AT THE RADAR SCREEN AT 5 MI A YELLOW TARGET SHOWED UP WITH AN INDICATION OF 03 (300 BELOW US). I REMEMBERED THINKING WHY WASN'T HE POINTED OUT TO US AND THEN THINKING HE MUST BE GOING OUR WAY AND WOULDN'T BE A FACTOR. AT THAT POINT WE GOT A RA (RESOLUTION ADVISORY) OF CLB, CLB. THE F/O SAID IT WANTS YOU TO PULL UP. AS I PULLED UP I LOOK AT THE V/V IT SHOWED A RED INDICATION (RED ARC) FOR DSNT AL THE WAY TO 1500 FPM CLB. I NEVER DID SEE THE GREEN ARC. THE F/O SAID AT FIRST GLANCE HE DIDN'T EITHER BUT DID SEE IT LATER. COULD HAVE BEEN THE TOP OF THE INSTRUMENT CUT OUT THE VIEW OF THE GREEN ARC SINCE THE GREEN ARC IS THE FURTHEST FROM THE CTR OF THE INSTRUMENT OR IT COULD BE THAT THE GREEN ARC IS ONLY 3 DOTS LONG ND DOESN'T STAND OUT. I CLBED AT 1500 FPM OR GREATER. WE XED OVER THE TFC. THE READOUT SHOWED HIM RED DIRECTLY UNDER US AND -10 (1000' BELOW). THE ALTIMETER SHOWED 12800'. THE F/O SPOTTED HIM JUST PRIOR TO US PASSING HIM. WE TOLD APCH WE WERE TAKING ACTION TO AVOID TFC AS INDICATED BY THE TCAS. NEVER SAW THE TFC. F/O DID. SW RED SYMBOL DIRECTLY UNDER ACFT AND 1000' BELOW ON RADAR SCREEN. DON'T KNOW WHAT I WOULD HAVE DONE IF WE HAD TFC ABOVE US AND HAD GOTTEN A SEC RESOLUTION ADVISORY TO NOT CLB. LIKED TO THINK I WOULD HAVE LEVELED OFF AND FLOWN BTWN THEM. DON'T KNOW.

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.