Narrative:

Air carrier X northbound at FL290, cpr Y sbound was climbed to FL290, while FL280 was entered in data block. Did not realize aircraft were in conflict until traffic call was made and cpr Y questioned his altitude assignment. Turned both aircraft and descended cpr Y to FL280. Supplemental information from acn 238720: air carrier X at FL290, approximately vills intersection on J79. Center advised us of cpr Y sbound traffic 12 O'clock at FL280. Shortly after we heard cpr Y report on level at FL290. Center asked him to confirm he was level at FL280 and he said no, he was cleared to FL290 and he was at FL290. Center gave him an immediate left turn to 090 degrees and us an immediate left turn to 270 degrees. Just as we started the turn we saw him. TCASII said traffic, descend, clear of traffic. It was of little value because it responded too late. Talked to center after landing, controller had cleared both aircraft to FL290. Controller's vectors were good in separating aircraft. This just emphasizes the need to listen up and maintain situational awareness, and constantly clear for traffic. Supplemental information from acn 238716: while cruising at FL290, ATC instructed an immediate left turn. TCASII then directed a descent. We picked up a visual on traffic, evasive maneuver was required to avoid a near miss.

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Original NASA ASRS Text

Title: ACR X AND CPR Y OPPOSITE DIRECTION TFC SAME ALT ASSIGNED HAD LTSS. ACR X TCASII RA EVASIVE ACTION TAKEN. SYS ERROR.

Narrative: ACR X NBOUND AT FL290, CPR Y SBOUND WAS CLBED TO FL290, WHILE FL280 WAS ENTERED IN DATA BLOCK. DID NOT REALIZE ACFT WERE IN CONFLICT UNTIL TFC CALL WAS MADE AND CPR Y QUESTIONED HIS ALT ASSIGNMENT. TURNED BOTH ACFT AND DSNDED CPR Y TO FL280. SUPPLEMENTAL INFO FROM ACN 238720: ACR X AT FL290, APPROX VILLS INTXN ON J79. CTR ADVISED US OF CPR Y SBOUND TFC 12 O'CLOCK AT FL280. SHORTLY AFTER WE HEARD CPR Y RPT ON LEVEL AT FL290. CTR ASKED HIM TO CONFIRM HE WAS LEVEL AT FL280 AND HE SAID NO, HE WAS CLRED TO FL290 AND HE WAS AT FL290. CTR GAVE HIM AN IMMEDIATE L TURN TO 090 DEGS AND US AN IMMEDIATE L TURN TO 270 DEGS. JUST AS WE STARTED THE TURN WE SAW HIM. TCASII SAID TFC, DSND, CLR OF TFC. IT WAS OF LITTLE VALUE BECAUSE IT RESPONDED TOO LATE. TALKED TO CTR AFTER LNDG, CTLR HAD CLRED BOTH ACFT TO FL290. CTLR'S VECTORS WERE GOOD IN SEPARATING ACFT. THIS JUST EMPHASIZES THE NEED TO LISTEN UP AND MAINTAIN SITUATIONAL AWARENESS, AND CONSTANTLY CLR FOR TFC. SUPPLEMENTAL INFO FROM ACN 238716: WHILE CRUISING AT FL290, ATC INSTRUCTED AN IMMEDIATE L TURN. TCASII THEN DIRECTED A DSCNT. WE PICKED UP A VISUAL ON TFC, EVASIVE MANEUVER WAS REQUIRED TO AVOID A NEAR MISS.

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.