CAPT OF A MD SUPER 80 DIRECTED HIS FO TO LAND ON THE FIRST GIVEN PARALLEL RWY BEHIND A DEPARTING B747-400 THAT HAD JUST ROTATED ON TKOF CONTRARY TO THE TWR CTLR INSTRUCTIONS TO SIDE STEP TO THE SIDE FOR THE OTHER PARALLEL RWY.

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WE WERE ON THE CIVET ARR TO LAX. DURING THE ARR WE WERE GETTING NUMEROUS SPD AND HDG CHANGES MAKING IT DIFFICULT AND TROUBLESOME. ON FINAL FOR RWY 25R AT 1300 FT AGL TWR CLRED A B747-400 FOR TKOF. I TOLD THE FO WHO WAS FLYING TO BE READY FOR THE GAR. THE B747 WAS TYPICALLY SLOW AND DID NOT GET LINED UP AND BEGIN HIS TKOF UNTIL WE WERE ABOUT 500 FT AGL. AT 200 FT AGL THE B747 WAS STILL ROLLING WHEN TWR TOLD US TO SIDE-STEP TO RWY 25L AND CLRED TO LAND. AT 200 FT AGL THIS MANEUVER IS FOOLHARDY AND UNSAFE SO I REPLIED UNABLE. AT 100 FT AGL WE WERE READY TO GAR WHEN THE B747 STARTED TO ROTATE. WE CONTINUED AND LANDED ON THE EARLY PART OF RWY 25R TO STAY OUT OF HIS WAKE. AFTER LNDG I HAD WORDS WITH THE TWR CHIEF OVER THE PHONE. THIS IS THE 3RD TIME I HAVE GIVEN THIS EXACT SIT FROM LAX TWR AND HAVE SPOKEN TO THEM ABOUT IT ON EVERY OCCASION. I FEEL THAT THEY FAIL TO GRASP THE GRAVITY AND SERIOUSNESS OF THIS SIT THAT THEY CREATE WITH THESE DANGEROUS AND UNPROFESSIONAL ACTIONS. YOU HAVE A HEAVILY LOADED B747 THAT CANNOT MOVE BUT VERY SLOWLY THAT CREATES DANGEROUS WAKE TURB ON HIS TKOF ROLL ALONE AND LAX TWR TRIES TO SNEAK ANOTHER ACFT AS HE IS LIFTING OFF. IF THE LNDG ACFT HAPPENS TO LAND A LITTLE TOO LONG HE WILL GET CAUGHT IN HIS WAKE AT LOW AIRSPD AND IDLE THRUST. IF ON THE OTHER HAND THE DEPARTING ACFT WOULD ABORT TKOF AND THE LNDG ACFT DOES NOT CATCH THE SIT IN TIME TO GAR WE WILL HAVE A DISASTER. I WILL NOT ALLOW SUCH A SIT TO HAPPEN AGAIN AS I WILL GAR AND LAND WHEN IT IS SAFE OR DIVERT TO ANOTHER ARPT WHERE IT IS SAFE OR EVEN DECLARE AN EMER IF THE SIT ATC CREATES GETS TOO DANGEROUS.