Narrative:

We were given a visual clearance to runway 24R; with a B747 4-5 mi ahead for runway 24L. The winds were about 240 degrees at 11 KTS; which helped to blow the wake into our path. We rolled right then left; recovered; and climbed to 2000 ft for vectors for another approach. Lessons learned: I will not follow a B747 to a parallel runway in any conditions; unless I am well above his path and can confirm his altitude path. Just because it is legal separation; does not make it right. I'll use better judgement and extend another 3 mi at least required separation between large and smaller aircraft must be greater if the larger aircraft is ahead and going to parallel; but close runways.

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Original NASA ASRS Text

Title: A B737-400 ON VISUAL APCH TO LAX ENCOUNTERED WAKE TURB FROM B747 ON PARALLEL RWYS. APCH BECAME UNSTABILIZED SO THEY EXECUTED A GAR.

Narrative: WE WERE GIVEN A VISUAL CLRNC TO RWY 24R; WITH A B747 4-5 MI AHEAD FOR RWY 24L. THE WINDS WERE ABOUT 240 DEGS AT 11 KTS; WHICH HELPED TO BLOW THE WAKE INTO OUR PATH. WE ROLLED R THEN L; RECOVERED; AND CLBED TO 2000 FT FOR VECTORS FOR ANOTHER APCH. LESSONS LEARNED: I WILL NOT FOLLOW A B747 TO A PARALLEL RWY IN ANY CONDITIONS; UNLESS I AM WELL ABOVE HIS PATH AND CAN CONFIRM HIS ALT PATH. JUST BECAUSE IT IS LEGAL SEPARATION; DOES NOT MAKE IT RIGHT. I'LL USE BETTER JUDGEMENT AND EXTEND ANOTHER 3 MI AT LEAST REQUIRED SEPARATION BTWN LARGE AND SMALLER ACFT MUST BE GREATER IF THE LARGER ACFT IS AHEAD AND GOING TO PARALLEL; BUT CLOSE RWYS.

Data retrieved from NASA's ASRS site as of January 2009 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.