Narrative:

Visual approach into sfo. Windy day with all aircraft landing and departing the 28 runways. Winds: 270 at 30 gusting 38. We were originally told to expect tip toe visual runway 28L and then told to expect quiet bridge visibility runway 28R; then cleared the 'tip toe runway 28L.' we questioned ATC and then were told cancel approach clearance. Then cleared 'visual runway 28R and maintain 180 KTS to 6 DME.' we were flaps configuration one with a strong headwind so no need for more drag I held off on more flaps and gear until slowing at the bridge. We were on the autopilot stabilized on the ILS runway 28R. At the bridge I called 'gear down flaps 2' and managed the speed. At that moment sfo tower switched told us change to and cleared to land runway 28L. I disconnected the autopilot and turned off the flight directors beginning a turn toward runway 28L. The first officer was busy setting up the runway 28L approach in the FMS. I called for flaps 3. I noticed that the airplane wasn't slowing down as I expected; but I thought that we were getting a lot of lift and updrafts from the wind. When I called for flaps full landing checklist we got the crc and red warning that the gear wasn't down. I called for gear down and made the decision to continue the approach knowing that I had plenty of time to get the gear down before landing or execute a go around. The gear took longer than I expected to come down; but it was down and locked by about 500 ft. I never felt as though the safety of flight was in jeopardy because I had ample time to execute a go around. The system worked to 'remind' us as designed. I think that the cause was the distraction of a runway change while configuring for landing combined with fatigue. When calling for an action make sure to assure that the action is taken. When distrs occur make sure to double check what you are doing.

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Original NASA ASRS Text

Title: MULTIPLE RWY CHANGES ON FINAL APCH CONTRIBUTE TO LATE LNDG GEAR EXTENSION FOR FATIGUED A319 FLT CREW.

Narrative: VISUAL APCH INTO SFO. WINDY DAY WITH ALL ACFT LNDG AND DEPARTING THE 28 RUNWAYS. WINDS: 270 AT 30 GUSTING 38. WE WERE ORIGINALLY TOLD TO EXPECT TIP TOE VISUAL RWY 28L AND THEN TOLD TO EXPECT QUIET BRIDGE VIS RWY 28R; THEN CLEARED THE 'TIP TOE RWY 28L.' WE QUESTIONED ATC AND THEN WERE TOLD CANCEL APCH CLRNC. THEN CLEARED 'VISUAL RWY 28R AND MAINTAIN 180 KTS TO 6 DME.' WE WERE FLAPS CONFIG ONE WITH A STRONG HEADWIND SO NO NEED FOR MORE DRAG I HELD OFF ON MORE FLAPS AND GEAR UNTIL SLOWING AT THE BRIDGE. WE WERE ON THE AUTOPILOT STABILIZED ON THE ILS RWY 28R. AT THE BRIDGE I CALLED 'GEAR DOWN FLAPS 2' AND MANAGED THE SPEED. AT THAT MOMENT SFO TOWER SWITCHED TOLD US CHANGE TO AND CLEARED TO LAND RWY 28L. I DISCONNECTED THE AUTOPILOT AND TURNED OFF THE FLT DIRECTORS BEGINNING A TURN TOWARD RWY 28L. THE FO WAS BUSY SETTING UP THE RWY 28L APCH IN THE FMS. I CALLED FOR FLAPS 3. I NOTICED THAT THE AIRPLANE WASN'T SLOWING DOWN AS I EXPECTED; BUT I THOUGHT THAT WE WERE GETTING A LOT OF LIFT AND UPDRAFTS FROM THE WIND. WHEN I CALLED FOR FLAPS FULL LNDG CHKLIST WE GOT THE CRC AND RED WARNING THAT THE GEAR WASN'T DOWN. I CALLED FOR GEAR DOWN AND MADE THE DECISION TO CONTINUE THE APCH KNOWING THAT I HAD PLENTY OF TIME TO GET THE GEAR DOWN BEFORE LNDG OR EXECUTE A GO AROUND. THE GEAR TOOK LONGER THAN I EXPECTED TO COME DOWN; BUT IT WAS DOWN AND LOCKED BY ABOUT 500 FT. I NEVER FELT AS THOUGH THE SAFETY OF FLT WAS IN JEOPARDY BECAUSE I HAD AMPLE TIME TO EXECUTE A GO AROUND. THE SYSTEM WORKED TO 'REMIND' US AS DESIGNED. I THINK THAT THE CAUSE WAS THE DISTR OF A RWY CHANGE WHILE CONFIGURING FOR LNDG COMBINED WITH FATIGUE. WHEN CALLING FOR AN ACTION MAKE SURE TO ASSURE THAT THE ACTION IS TAKEN. WHEN DISTRS OCCUR MAKE SURE TO DOUBLE CHK WHAT YOU ARE DOING.

Data retrieved from NASA's ASRS site as of May 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.