Narrative:

Busy, clear, calm, beautiful sunny day in atlanta. Heading wbound on downwind for runway 8L, with airport in sight. ATC cleared us to turn southeast (150 degrees, I think) and cleared us for the visual to runway 8L. During the turn ATC said 'I turned you too soon, turn right 20 degrees.' and that, I believe, is where the trouble began. I called back '20 degrees from what heading?' there was no reply, the frequency was very busy. We picked a heading of 180 degrees. First chance, I asked 'is a heading of south ok?' reply: 'no, turn right heading 230 degrees.' we did, and in rapid succession got 2 TA's and 1 RA from the TCASII as we crossed the finals for runways 8L and 9R. Traffic passed 500 ft over and under us. The RA called for no deviation, but to not descend. We complied and shortly thereafter were reclred for the visual. I believe this was all precipitated by the ambiguous 'turn right 20 degrees' during a turn. I've heard it before from ATC and have been mystified as to what heading they really wanted.

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Original NASA ASRS Text

Title: B717 FLC QUESTION APCH CTLR REQUEST FOR A 20 DEG R TURN WITHOUT A SPECIFIED HEADING DURING VECTORS TO A VISUAL APCH.

Narrative: BUSY, CLR, CALM, BEAUTIFUL SUNNY DAY IN ATLANTA. HEADING WBOUND ON DOWNWIND FOR RWY 8L, WITH ARPT IN SIGHT. ATC CLRED US TO TURN SE (150 DEGS, I THINK) AND CLRED US FOR THE VISUAL TO RWY 8L. DURING THE TURN ATC SAID 'I TURNED YOU TOO SOON, TURN R 20 DEGS.' AND THAT, I BELIEVE, IS WHERE THE TROUBLE BEGAN. I CALLED BACK '20 DEGS FROM WHAT HEADING?' THERE WAS NO REPLY, THE FREQ WAS VERY BUSY. WE PICKED A HEADING OF 180 DEGS. FIRST CHANCE, I ASKED 'IS A HEADING OF S OK?' REPLY: 'NO, TURN R HEADING 230 DEGS.' WE DID, AND IN RAPID SUCCESSION GOT 2 TA'S AND 1 RA FROM THE TCASII AS WE CROSSED THE FINALS FOR RWYS 8L AND 9R. TFC PASSED 500 FT OVER AND UNDER US. THE RA CALLED FOR NO DEV, BUT TO NOT DSND. WE COMPLIED AND SHORTLY THEREAFTER WERE RECLRED FOR THE VISUAL. I BELIEVE THIS WAS ALL PRECIPITATED BY THE AMBIGUOUS 'TURN R 20 DEGS' DURING A TURN. I'VE HEARD IT BEFORE FROM ATC AND HAVE BEEN MYSTIFIED AS TO WHAT HEADING THEY REALLY WANTED.

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.