Narrative:

ZFW had us on vectors at 13000 ft MSL for separation from other IFR traffic on our descent into sat when they pointed out VFR traffic at our 10 O'clock position. My first officer and the jump seat rider got a visual on the aircraft and mentioned they just saw a large group of jumpers exiting the aircraft. I then saw the target but never any jumpers. The traffic was getting larger and was frozen on the windscreen so I knew it was a potential conflict. At about this time we got a TCASII RA of 'monitor vertical speed.' I disconnected the autoplt to be ready for evasive action and continued to watch the traffic. I didn't know if the traffic was changing altitude but I thought it might be. I was distraction by the TCASII warning and allowed the aircraft to slow and start a shallow descent. The RA now goes to a 'climb.' I looked back inside to see my altitude at 12800 ft MSL and the vsi continuing to show a large red arc. I added power and climbed back up to about 13200 ft MSL and the TCASII warning ceased. No complaint was made by center as to our altitude. Additional factors: the sun was in our eyes and it was difficult to see inside after looking out at the traffic. Autothrottles weren't working. I made this situation worse by disconnecting the autoplt and allowing the aircraft to descend. The autothrottles weren't working as they normally are and this further complicated the situation because we got slow, too. I had trouble seeing the vsi because of glare. The fact that the TCASII had a red RA target and was telling me to do something made me feel like I needed to take action. In the future I will stay inside and ask the first officer to look for the traffic. This way I will be able to better interpretation the resolution action. Monitor vertical speed, if in level flight, means stay level, do nothing, but be ready to do something. If I had an RA of 'monitor vertical speed' in a descent, I might need to change my descent rate. I plan to review the TCASII system and chair fly myself through the different scenarios.

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Original NASA ASRS Text

Title: AN MD90 IS GIVEN VFR TFC BY ZFW WHICH BECOMES A TCASII RA WHEN THE PIC LOSES HIS SITUATIONAL AWARENESS REGARDING THE SEPARATION CRITERION.

Narrative: ZFW HAD US ON VECTORS AT 13000 FT MSL FOR SEPARATION FROM OTHER IFR TFC ON OUR DSCNT INTO SAT WHEN THEY POINTED OUT VFR TFC AT OUR 10 O'CLOCK POS. MY FO AND THE JUMP SEAT RIDER GOT A VISUAL ON THE ACFT AND MENTIONED THEY JUST SAW A LARGE GROUP OF JUMPERS EXITING THE ACFT. I THEN SAW THE TARGET BUT NEVER ANY JUMPERS. THE TFC WAS GETTING LARGER AND WAS FROZEN ON THE WINDSCREEN SO I KNEW IT WAS A POTENTIAL CONFLICT. AT ABOUT THIS TIME WE GOT A TCASII RA OF 'MONITOR VERT SPD.' I DISCONNECTED THE AUTOPLT TO BE READY FOR EVASIVE ACTION AND CONTINUED TO WATCH THE TFC. I DIDN'T KNOW IF THE TFC WAS CHANGING ALT BUT I THOUGHT IT MIGHT BE. I WAS DISTR BY THE TCASII WARNING AND ALLOWED THE ACFT TO SLOW AND START A SHALLOW DSCNT. THE RA NOW GOES TO A 'CLB.' I LOOKED BACK INSIDE TO SEE MY ALT AT 12800 FT MSL AND THE VSI CONTINUING TO SHOW A LARGE RED ARC. I ADDED PWR AND CLBED BACK UP TO ABOUT 13200 FT MSL AND THE TCASII WARNING CEASED. NO COMPLAINT WAS MADE BY CTR AS TO OUR ALT. ADDITIONAL FACTORS: THE SUN WAS IN OUR EYES AND IT WAS DIFFICULT TO SEE INSIDE AFTER LOOKING OUT AT THE TFC. AUTOTHROTTLES WEREN'T WORKING. I MADE THIS SIT WORSE BY DISCONNECTING THE AUTOPLT AND ALLOWING THE ACFT TO DSND. THE AUTOTHROTTLES WEREN'T WORKING AS THEY NORMALLY ARE AND THIS FURTHER COMPLICATED THE SIT BECAUSE WE GOT SLOW, TOO. I HAD TROUBLE SEEING THE VSI BECAUSE OF GLARE. THE FACT THAT THE TCASII HAD A RED RA TARGET AND WAS TELLING ME TO DO SOMETHING MADE ME FEEL LIKE I NEEDED TO TAKE ACTION. IN THE FUTURE I WILL STAY INSIDE AND ASK THE FO TO LOOK FOR THE TFC. THIS WAY I WILL BE ABLE TO BETTER INTERP THE RESOLUTION ACTION. MONITOR VERT SPD, IF IN LEVEL FLT, MEANS STAY LEVEL, DO NOTHING, BUT BE READY TO DO SOMETHING. IF I HAD AN RA OF 'MONITOR VERT SPD' IN A DSCNT, I MIGHT NEED TO CHANGE MY DSCNT RATE. I PLAN TO REVIEW THE TCASII SYS AND CHAIR FLY MYSELF THROUGH THE DIFFERENT SCENARIOS.

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.