Narrative:

While on final approach into sjc, flaps 30 degrees was selected. I noticed while going past flaps 10 degrees the aircraft equipped more and more right aileron to keep wings level (up to 20 degrees). Power setting was noted equal, wind was no factor, flap indicator showed no split flap and overhead flap indicator showed normal indication. While checking problem, aircraft drifted to runway 30R centerline. First officer noted line up problem and then tower, so I corrected back to runway 30L centerline and landed without incident. The aircraft was flown 1 leg earlier (sat to phx) by the first officer. When landing in phx, the wind was highly variable with dust storms in the outlying area, so it was hard to determine if the problem existed on the previous flight. Callback conversation with reporter revealed the following information: the reporter stated that there were no indications on the flight deck of a split flap condition. He followed the status of the aircraft and found out that the next day, during a ferry flight, 2 maintenance technicians were on board. As the flaps were extended, each technician monitored the flaps from inside the aircraft. Though no split flap indications were noted on the flight deck, one of the flaps kept coming up. The reporter stated that the aircraft was down for maintenance for 2 or more days. This was his first experience with a split flap problem on a B737.

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Original NASA ASRS Text

Title: A B737-200 CAPT INITIALLY EXPERIENCED A FLAP PROB WHICH CONTRIBUTED TO A WRONG RWY APCH.

Narrative: WHILE ON FINAL APCH INTO SJC, FLAPS 30 DEGS WAS SELECTED. I NOTICED WHILE GOING PAST FLAPS 10 DEGS THE ACFT EQUIPPED MORE AND MORE R AILERON TO KEEP WINGS LEVEL (UP TO 20 DEGS). PWR SETTING WAS NOTED EQUAL, WIND WAS NO FACTOR, FLAP INDICATOR SHOWED NO SPLIT FLAP AND OVERHEAD FLAP INDICATOR SHOWED NORMAL INDICATION. WHILE CHKING PROB, ACFT DRIFTED TO RWY 30R CTRLINE. FO NOTED LINE UP PROB AND THEN TWR, SO I CORRECTED BACK TO RWY 30L CTRLINE AND LANDED WITHOUT INCIDENT. THE ACFT WAS FLOWN 1 LEG EARLIER (SAT TO PHX) BY THE FO. WHEN LNDG IN PHX, THE WIND WAS HIGHLY VARIABLE WITH DUST STORMS IN THE OUTLYING AREA, SO IT WAS HARD TO DETERMINE IF THE PROB EXISTED ON THE PREVIOUS FLT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT THERE WERE NO INDICATIONS ON THE FLT DECK OF A SPLIT FLAP CONDITION. HE FOLLOWED THE STATUS OF THE ACFT AND FOUND OUT THAT THE NEXT DAY, DURING A FERRY FLT, 2 MAINT TECHNICIANS WERE ON BOARD. AS THE FLAPS WERE EXTENDED, EACH TECHNICIAN MONITORED THE FLAPS FROM INSIDE THE ACFT. THOUGH NO SPLIT FLAP INDICATIONS WERE NOTED ON THE FLT DECK, ONE OF THE FLAPS KEPT COMING UP. THE RPTR STATED THAT THE ACFT WAS DOWN FOR MAINT FOR 2 OR MORE DAYS. THIS WAS HIS FIRST EXPERIENCE WITH A SPLIT FLAP PROB ON A B737.

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.