Narrative:

Air carrier, MD88, sebound to rmg, landing atl. GA, beech king air departed from bna. King air was climbing to FL280, MD88 level at FL250. When king air out of FL244, conflict alert activated. Aircraft were approximately 6 mi apart. MD88 on my frequency, king air on R26 (jks hi sector) frequency. I called traffic to MD88 at 10 O'clock position, 3 mi at FL250 (king air mode C). MD88 responded, 'I'll get back to you,' and executed TCASII RA. R26 descended king air to FL240. TCASII ordered descent also, on MD88. Targets merged at same altitude. MD88 informed me of TCASII RA after returning to FL250. No injuries. King air was not TCASII equipped. Supplemental information from acn 394079: level at FL250 noted a target on TCASII and then visually at about 11 O'clock position, co-altitude headed towards us. As target came inside 10 NM a right turn was initiated to insure target would pass behind us. Another target was on TCASII at FL240. As right bank began TCASII RA 'descend' annunciated with vsi green arc at -3000 FPM. Autoplt was disconnected and descent initiated. As the target at FL250 passed above and behind, a 'climb now' RA annunciated because of the target at FL240. A pull up was begun and 'clear of conflict' annunciated as soon as descent was arrested at FL245. The controller was advised of the RA and said he was not working the traffic at our altitude. A total of about 30-45 seconds elapsed from initial sighting to 'clear of conflict' annunciation. An explanation of the co-altitude traffic was not given, but I feel it was either a military aircraft or a controller handoff problem. There was higher than normal traffic volume at the mid altitudes due to turbulence higher. The heads-up provided by the TCASII display prevented a total surprise when the RA annunciated.

Related reports:

Google
 

Original NASA ASRS Text

Title: AN ARTCC CTLR OBSERVES A KING AIR LOSE SEPARATION WITH AN MD88 IN HIS SECTOR AT ZME, TN.

Narrative: ACR, MD88, SEBOUND TO RMG, LNDG ATL. GA, BEECH KING AIR DEPARTED FROM BNA. KING AIR WAS CLBING TO FL280, MD88 LEVEL AT FL250. WHEN KING AIR OUT OF FL244, CONFLICT ALERT ACTIVATED. ACFT WERE APPROX 6 MI APART. MD88 ON MY FREQ, KING AIR ON R26 (JKS HI SECTOR) FREQ. I CALLED TFC TO MD88 AT 10 O'CLOCK POS, 3 MI AT FL250 (KING AIR MODE C). MD88 RESPONDED, 'I'LL GET BACK TO YOU,' AND EXECUTED TCASII RA. R26 DSNDED KING AIR TO FL240. TCASII ORDERED DSCNT ALSO, ON MD88. TARGETS MERGED AT SAME ALT. MD88 INFORMED ME OF TCASII RA AFTER RETURNING TO FL250. NO INJURIES. KING AIR WAS NOT TCASII EQUIPPED. SUPPLEMENTAL INFO FROM ACN 394079: LEVEL AT FL250 NOTED A TARGET ON TCASII AND THEN VISUALLY AT ABOUT 11 O'CLOCK POS, CO-ALT HEADED TOWARDS US. AS TARGET CAME INSIDE 10 NM A R TURN WAS INITIATED TO INSURE TARGET WOULD PASS BEHIND US. ANOTHER TARGET WAS ON TCASII AT FL240. AS R BANK BEGAN TCASII RA 'DSND' ANNUNCIATED WITH VSI GREEN ARC AT -3000 FPM. AUTOPLT WAS DISCONNECTED AND DSCNT INITIATED. AS THE TARGET AT FL250 PASSED ABOVE AND BEHIND, A 'CLB NOW' RA ANNUNCIATED BECAUSE OF THE TARGET AT FL240. A PULL UP WAS BEGUN AND 'CLR OF CONFLICT' ANNUNCIATED AS SOON AS DSCNT WAS ARRESTED AT FL245. THE CTLR WAS ADVISED OF THE RA AND SAID HE WAS NOT WORKING THE TFC AT OUR ALT. A TOTAL OF ABOUT 30-45 SECONDS ELAPSED FROM INITIAL SIGHTING TO 'CLR OF CONFLICT' ANNUNCIATION. AN EXPLANATION OF THE CO-ALT TFC WAS NOT GIVEN, BUT I FEEL IT WAS EITHER A MIL ACFT OR A CTLR HDOF PROB. THERE WAS HIGHER THAN NORMAL TFC VOLUME AT THE MID ALTS DUE TO TURB HIGHER. THE HEADS-UP PROVIDED BY THE TCASII DISPLAY PREVENTED A TOTAL SURPRISE WHEN THE RA ANNUNCIATED.

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.