Narrative:

We received a TCASII TA as we were descending and leveling at FL230 on arrival into cle. The TA was followed shortly by an RA with a red arc on the vertical speed indicator from 0- 2000 FPM descent, and a green arc from 2000 FPM to 2500 FPM. The captain disconnected the autoplt (block V with altitude capture) and initiated a descent to comply with the RA. The first officer transitioned outside to get a visual on the traffic, while at the same time, attempting to inform ATC of the deviation. Both pilots then got a visual on the traffic which was at FL220 and looked to be at 3 O'clock and 5 mi. After some initial frequency congestion, we informed ATC of the deviation. By now we were at FL222 and had leveled. The RA cleared and ATC instructed us to just continue to FL220. After some discussion on the ground, the crew felt that the TCASII had not realized that we were leveling at FL230 and sensed a conflict. Its solution was to instruct us to descend rapidly (2500 FPM) to clear traffic. We were practically level when the RA occurred, and feel there should never have been an RA issued. Perhaps TCASII is not capable of updating descent rates quickly enough to recognize that a level off is in progress and no conflict will occur. As it was, we were presented with a command to descend rapidly to avoid converging traffic below us, at the time we were leveling off. We chose to initially go with the TCASII guidance and sort out the details later.

Related reports:

Google
 

Original NASA ASRS Text

Title: FLC OF LGT DSNDING TO FL230 RECEIVED TCASII RA TO DSND. RA CLRED AT 22200 AND TFC WAS VISUALLY ACQUIRED 5 MI APPEARING TO BE AT FL220.

Narrative: WE RECEIVED A TCASII TA AS WE WERE DSNDING AND LEVELING AT FL230 ON ARR INTO CLE. THE TA WAS FOLLOWED SHORTLY BY AN RA WITH A RED ARC ON THE VERT SPD INDICATOR FROM 0- 2000 FPM DSCNT, AND A GREEN ARC FROM 2000 FPM TO 2500 FPM. THE CAPT DISCONNECTED THE AUTOPLT (BLOCK V WITH ALT CAPTURE) AND INITIATED A DSCNT TO COMPLY WITH THE RA. THE FO TRANSITIONED OUTSIDE TO GET A VISUAL ON THE TFC, WHILE AT THE SAME TIME, ATTEMPTING TO INFORM ATC OF THE DEV. BOTH PLTS THEN GOT A VISUAL ON THE TFC WHICH WAS AT FL220 AND LOOKED TO BE AT 3 O'CLOCK AND 5 MI. AFTER SOME INITIAL FREQ CONGESTION, WE INFORMED ATC OF THE DEV. BY NOW WE WERE AT FL222 AND HAD LEVELED. THE RA CLRED AND ATC INSTRUCTED US TO JUST CONTINUE TO FL220. AFTER SOME DISCUSSION ON THE GND, THE CREW FELT THAT THE TCASII HAD NOT REALIZED THAT WE WERE LEVELING AT FL230 AND SENSED A CONFLICT. ITS SOLUTION WAS TO INSTRUCT US TO DSND RAPIDLY (2500 FPM) TO CLR TFC. WE WERE PRACTICALLY LEVEL WHEN THE RA OCCURRED, AND FEEL THERE SHOULD NEVER HAVE BEEN AN RA ISSUED. PERHAPS TCASII IS NOT CAPABLE OF UPDATING DSCNT RATES QUICKLY ENOUGH TO RECOGNIZE THAT A LEVEL OFF IS IN PROGRESS AND NO CONFLICT WILL OCCUR. AS IT WAS, WE WERE PRESENTED WITH A COMMAND TO DSND RAPIDLY TO AVOID CONVERGING TFC BELOW US, AT THE TIME WE WERE LEVELING OFF. WE CHOSE TO INITIALLY GO WITH THE TCASII GUIDANCE AND SORT OUT THE DETAILS LATER.

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.