Narrative:

Air carrier X, large transport wbound requesting FL390, climbed to FL270 inadvertently, meant to climb air carrier X to FL260 (which was temporarily assigned in data block). Also called opposite direction traffic at FL270. Air carrier X read back climb to FL270. I missed readback. Air carrier Y eastbound at FL270. I called air carrier Y as traffic to air carrier X. Approximately 10 mi apart (head-on). I observed mode C of air carrier X 260+ (262, 264, climbing). I told air carrier X maintain FL260. Air carrier X asked to verify descent. I turned air carrier X to 360 heading, then air carrier Y southbound, 120, then 180 heading. I then climbed air carrier X to FL330, expedite thru FL280, then immediate climb thru FL280. Standard separation lost. Head on closure rate was very fast. Air carrier X had air carrier Y in sight when traffic called. Callback conversation with reporter revealed the following: the reporter stated that she never restated descent back to FL260. She thought she could keep aircraft separated by vector headings. She saw the conflict coming but took action too late. Computer detection did go off after she had issued vector headings. Supplemental information from acn 123680: air carrier X was given climb to FL270. A few mins after level at FL270, the controller directed descent to FL260. No urgent action was communicated. We questioned descent instead of a climb. We reconfirmed 360 degree heading and again questioned what altitude was desired. We were then given an immediate climb to FL280 and we acknowledged. A different controller came on frequency and directed a climb to FL330 and direct to ginns intersection. Secondarily, to conflict situation, was the safety factor of completing flight after being notified in flight of violation. Safety factor of my crew keeping our attention on the details of completing the flight safely, us trying to remember each event that led to the conflict, and were we at fault or ARTCC. Thirdly, no one to contact upon landing to find more information, after hours, even though controllers could replay tapes immediately and learn the causes, while the flight crew would not know until the following day (additional trip segments to be flown, drive home, etc, with our minds not on our primary tasks, but the situation that had occurred).

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Original NASA ASRS Text

Title: ACR X HAD LESS THAN STANDARD SEPARATION FROM ACR Y. SYSTEM ERROR.

Narrative: ACR X, LGT WBOUND REQUESTING FL390, CLIMBED TO FL270 INADVERTENTLY, MEANT TO CLIMB ACR X TO FL260 (WHICH WAS TEMPORARILY ASSIGNED IN DATA BLOCK). ALSO CALLED OPPOSITE DIRECTION TFC AT FL270. ACR X READ BACK CLIMB TO FL270. I MISSED READBACK. ACR Y EBND AT FL270. I CALLED ACR Y AS TFC TO ACR X. APPROX 10 MI APART (HEAD-ON). I OBSERVED MODE C OF ACR X 260+ (262, 264, CLIMBING). I TOLD ACR X MAINTAIN FL260. ACR X ASKED TO VERIFY DSCNT. I TURNED ACR X TO 360 HDG, THEN ACR Y SBND, 120, THEN 180 HDG. I THEN CLIMBED ACR X TO FL330, EXPEDITE THRU FL280, THEN IMMEDIATE CLIMB THRU FL280. STANDARD SEPARATION LOST. HEAD ON CLOSURE RATE WAS VERY FAST. ACR X HAD ACR Y IN SIGHT WHEN TFC CALLED. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: THE REPORTER STATED THAT SHE NEVER RESTATED DSCNT BACK TO FL260. SHE THOUGHT SHE COULD KEEP ACFT SEPARATED BY VECTOR HDGS. SHE SAW THE CONFLICT COMING BUT TOOK ACTION TOO LATE. COMPUTER DETECTION DID GO OFF AFTER SHE HAD ISSUED VECTOR HDGS. SUPPLEMENTAL INFORMATION FROM ACN 123680: ACR X WAS GIVEN CLIMB TO FL270. A FEW MINS AFTER LEVEL AT FL270, THE CTLR DIRECTED DSCNT TO FL260. NO URGENT ACTION WAS COMMUNICATED. WE QUESTIONED DSCNT INSTEAD OF A CLIMB. WE RECONFIRMED 360 DEG HDG AND AGAIN QUESTIONED WHAT ALT WAS DESIRED. WE WERE THEN GIVEN AN IMMEDIATE CLIMB TO FL280 AND WE ACKNOWLEDGED. A DIFFERENT CTLR CAME ON FREQ AND DIRECTED A CLIMB TO FL330 AND DIRECT TO GINNS INTXN. SECONDARILY, TO CONFLICT SITUATION, WAS THE SAFETY FACTOR OF COMPLETING FLT AFTER BEING NOTIFIED IN FLT OF VIOLATION. SAFETY FACTOR OF MY CREW KEEPING OUR ATTN ON THE DETAILS OF COMPLETING THE FLT SAFELY, US TRYING TO REMEMBER EACH EVENT THAT LED TO THE CONFLICT, AND WERE WE AT FAULT OR ARTCC. THIRDLY, NO ONE TO CONTACT UPON LNDG TO FIND MORE INFO, AFTER HOURS, EVEN THOUGH CTLRS COULD REPLAY TAPES IMMEDIATELY AND LEARN THE CAUSES, WHILE THE FLT CREW WOULD NOT KNOW UNTIL THE FOLLOWING DAY (ADDITIONAL TRIP SEGMENTS TO BE FLOWN, DRIVE HOME, ETC, WITH OUR MINDS NOT ON OUR PRIMARY TASKS, BUT THE SITUATION THAT HAD OCCURRED).

Data retrieved from NASA's ASRS site as of August 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.