Narrative:

I was working the ffo radar sector. The airplanes involved were: air carrier X T/757/G sna/pit air carrier Y T/727/a lga/stl air carrier zt/B757/G san/pit. X was issued a clearance to descend from FL410 to FL370 air carrier Y was wbound on J-80. At FL350 X was then issued a clearance to turn 20 degrees left for further descent. 20 seconds later Z was told to descend from FL410 to FL330. 6 seconds later X accepted and readback the clearance for Z. X, who was TCASII equipped did not begin his descent until 40 seconds had elapsed. He did not question the clearance even though he obviously knew air carrier Y was traffic. When the situation was noticed Z was questioned about his clearance. The reply from Z was, 'somebody else took that clearance.' this was 1 min and 20 seconds after the clearance was issued. At this time adep had already activated. Supplemental information from acn 285002: I had been working the ffo manual controller for 3 mins prior to error. Aircraft #1 -- air carrier Y T/B727/a via lga J-80 stl at FL350. Aircraft #2 -- air carrier X T/B757/G via sna direct ape pit descending FL330. X was issued a vector 20 degrees left for the descent into pit. 20 seconds later, company flight XXX (T/B757/G, also to pit) was cleared to descend and maintain FL330. X mistakenly took clearance and his readback was partially covered by other aircraft and adjacent sector call on handoff line. Conflict alert and adep activated 1 min and 20 seconds later as X passed 2 mi right and 1200 ft below Y. Upon questioning Z, if he had received/acknowledged descent to FL330 he responded, 'I think someone else took that clearance.' my concern is why did Z not question clearance if he thought it was for him.

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Original NASA ASRS Text

Title: ACR X RESPONSE TO WRONG CALL SIGN UNAUTH DSCNT THROUGH OCCUPIED ALT HAD LTSS FROM ACR Y. PLTDEV. SYS ERROR.

Narrative: I WAS WORKING THE FFO RADAR SECTOR. THE AIRPLANES INVOLVED WERE: ACR X T/757/G SNA/PIT ACR Y T/727/A LGA/STL ACR ZT/B757/G SAN/PIT. X WAS ISSUED A CLRNC TO DSND FROM FL410 TO FL370 ACR Y WAS WBOUND ON J-80. AT FL350 X WAS THEN ISSUED A CLRNC TO TURN 20 DEGS L FOR FURTHER DSCNT. 20 SECONDS LATER Z WAS TOLD TO DSND FROM FL410 TO FL330. 6 SECONDS LATER X ACCEPTED AND READBACK THE CLRNC FOR Z. X, WHO WAS TCASII EQUIPPED DID NOT BEGIN HIS DSCNT UNTIL 40 SECONDS HAD ELAPSED. HE DID NOT QUESTION THE CLRNC EVEN THOUGH HE OBVIOUSLY KNEW ACR Y WAS TFC. WHEN THE SIT WAS NOTICED Z WAS QUESTIONED ABOUT HIS CLRNC. THE REPLY FROM Z WAS, 'SOMEBODY ELSE TOOK THAT CLRNC.' THIS WAS 1 MIN AND 20 SECONDS AFTER THE CLRNC WAS ISSUED. AT THIS TIME ADEP HAD ALREADY ACTIVATED. SUPPLEMENTAL INFO FROM ACN 285002: I HAD BEEN WORKING THE FFO MANUAL CTLR FOR 3 MINS PRIOR TO ERROR. ACFT #1 -- ACR Y T/B727/A VIA LGA J-80 STL AT FL350. ACFT #2 -- ACR X T/B757/G VIA SNA DIRECT APE PIT DSNDING FL330. X WAS ISSUED A VECTOR 20 DEGS L FOR THE DSCNT INTO PIT. 20 SECONDS LATER, COMPANY FLT XXX (T/B757/G, ALSO TO PIT) WAS CLRED TO DSND AND MAINTAIN FL330. X MISTAKENLY TOOK CLRNC AND HIS READBACK WAS PARTIALLY COVERED BY OTHER ACFT AND ADJACENT SECTOR CALL ON HDOF LINE. CONFLICT ALERT AND ADEP ACTIVATED 1 MIN AND 20 SECONDS LATER AS X PASSED 2 MI R AND 1200 FT BELOW Y. UPON QUESTIONING Z, IF HE HAD RECEIVED/ACKNOWLEDGED DSCNT TO FL330 HE RESPONDED, 'I THINK SOMEONE ELSE TOOK THAT CLRNC.' MY CONCERN IS WHY DID Z NOT QUESTION CLRNC IF HE THOUGHT IT WAS FOR HIM.

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.