Narrative:

On approach to runway 28L at sfo, with landing clearance, noticed a B747 situated between threshold of runways 28L and 28R. At approximately 50 ft, encountered a sudden sink rate I thought associated with wind shift (winds on FMC indicated a 180 degree shift in last 200 ft). At under 45 ft, encountered significant turbulence (felt like B747 powering up to take position and hold on runway 28R). Initiated go around as a result of, now, unstabilized flight condition. Right main gear contacted ground during excessive wing rock. The B737 is not so nimble or responsive in the approach configuration, and not able to quickly correct for such wake encounters. During debrief of situation, I felt I was put in a position where prudence would dictate we fly purposefully above the GS, aiming for the 3000 ft marker. First officer commented that was not in the stabilized criteria air carrier X teaches. During changeover with new crew, several recent and similar incidents came to light: a 737 cleared to land on runway 28L with a B777 cleared for takeoff on runway 28R. B737's landing with any heavy positioned between closely spaced runways. Control of an aircraft close to the ground is limited by the responsiveness of said airplane, pilot reaction time, and altitude to maneuver. ATC is placing aircraft in harm's way when ignoring the very real dangers of wake turbulence to gain a few mins on the schedule.

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Original NASA ASRS Text

Title: A B737 CREW ON RWY 28L, SFO, SHORT FINAL RECEIVE JET BLAST FROM A B747 SITTING BTWN THE RWYS AND MOVING TO DEPART ON RWY 28R.

Narrative: ON APCH TO RWY 28L AT SFO, WITH LNDG CLRNC, NOTICED A B747 SITUATED BTWN THRESHOLD OF RWYS 28L AND 28R. AT APPROX 50 FT, ENCOUNTERED A SUDDEN SINK RATE I THOUGHT ASSOCIATED WITH WIND SHIFT (WINDS ON FMC INDICATED A 180 DEG SHIFT IN LAST 200 FT). AT UNDER 45 FT, ENCOUNTERED SIGNIFICANT TURBULENCE (FELT LIKE B747 POWERING UP TO TAKE POS AND HOLD ON RWY 28R). INITIATED GAR AS A RESULT OF, NOW, UNSTABILIZED FLT CONDITION. R MAIN GEAR CONTACTED GND DURING EXCESSIVE WING ROCK. THE B737 IS NOT SO NIMBLE OR RESPONSIVE IN THE APCH CONFIGURATION, AND NOT ABLE TO QUICKLY CORRECT FOR SUCH WAKE ENCOUNTERS. DURING DEBRIEF OF SIT, I FELT I WAS PUT IN A POSITION WHERE PRUDENCE WOULD DICTATE WE FLY PURPOSEFULLY ABOVE THE GS, AIMING FOR THE 3000 FT MARKER. FO COMMENTED THAT WAS NOT IN THE STABILIZED CRITERIA ACR X TEACHES. DURING CHANGEOVER WITH NEW CREW, SEVERAL RECENT AND SIMILAR INCIDENTS CAME TO LIGHT: A 737 CLRED TO LAND ON RWY 28L WITH A B777 CLRED FOR TKOF ON RWY 28R. B737'S LNDG WITH ANY HEAVY POSITIONED BTWN CLOSELY SPACED RWYS. CTL OF AN ACFT CLOSE TO THE GROUND IS LIMITED BY THE RESPONSIVENESS OF SAID AIRPLANE, PLT REACTION TIME, AND ALTITUDE TO MANEUVER. ATC IS PLACING ACFT IN HARM'S WAY WHEN IGNORING THE VERY REAL DANGERS OF WAKE TURBULENCE TO GAIN A FEW MINS ON THE SCHEDULE.

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.