Narrative:

We were on a vector for approach to runway 24R ILS. We were on a heading of 050 degrees approximately 15 mi east of lax. This distance is usually past the point at which we are turned onto the approach. Traffic was backed up and we were holding minimum speed to still allow a 30 degree angle of bank assigned 150 KTS. We were given instructions by approach control to turn right to (what we thought) a heading of 170 degrees. I heard 170 degrees (I was flying) and the first officer heard and read back 'turn right to a heading of 170 degrees.' a few seconds later, approach control asked us what our heading was. The first officer responded turning right through 150 degrees for 170 degrees. Approach control instructed us to turn back to a heading of 070 degrees immediately that we were not to turn to 170 degrees. We immediately turned left (30 degree angle of bank) to heading 070 degrees. No further occurrences were experienced. After the flight had terminated, the first officer and I were discussing the instructions and we still feel we heard 170 degrees. I know approach control at lax can get very hectic but that should indicate to the controller to speak instructions clearly and listen for the readback. After all, that is why we read back instruction.

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Original NASA ASRS Text

Title: GIVEN A TURN AND NEW HDG CLRNC, FLC READ BACK THE NEW HDG (BOTH PLTS HEARD 170 DEGS), BUT THE TRACON CTLR MISSED THE READBACK AND THEN, WHEN NOTING THE ACFT WAS CONTINUING A R TURN, QUESTIONED THEM AND INTERVENED WITH THE CORRECT HDG.

Narrative: WE WERE ON A VECTOR FOR APCH TO RWY 24R ILS. WE WERE ON A HDG OF 050 DEGS APPROX 15 MI E OF LAX. THIS DISTANCE IS USUALLY PAST THE POINT AT WHICH WE ARE TURNED ONTO THE APCH. TFC WAS BACKED UP AND WE WERE HOLDING MINIMUM SPD TO STILL ALLOW A 30 DEG ANGLE OF BANK ASSIGNED 150 KTS. WE WERE GIVEN INSTRUCTIONS BY APCH CTL TO TURN R TO (WHAT WE THOUGHT) A HDG OF 170 DEGS. I HEARD 170 DEGS (I WAS FLYING) AND THE FO HEARD AND READ BACK 'TURN R TO A HDG OF 170 DEGS.' A FEW SECONDS LATER, APCH CTL ASKED US WHAT OUR HDG WAS. THE FO RESPONDED TURNING R THROUGH 150 DEGS FOR 170 DEGS. APCH CTL INSTRUCTED US TO TURN BACK TO A HDG OF 070 DEGS IMMEDIATELY THAT WE WERE NOT TO TURN TO 170 DEGS. WE IMMEDIATELY TURNED L (30 DEG ANGLE OF BANK) TO HDG 070 DEGS. NO FURTHER OCCURRENCES WERE EXPERIENCED. AFTER THE FLT HAD TERMINATED, THE FO AND I WERE DISCUSSING THE INSTRUCTIONS AND WE STILL FEEL WE HEARD 170 DEGS. I KNOW APCH CTL AT LAX CAN GET VERY HECTIC BUT THAT SHOULD INDICATE TO THE CTLR TO SPEAK INSTRUCTIONS CLRLY AND LISTEN FOR THE READBACK. AFTER ALL, THAT IS WHY WE READ BACK INSTRUCTION.

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.