B737 flight crew on visual approach to left runway is switched to right runway by tower at 1500 ft. ...

Narrative:

Landing at ZZZ; we were cleared for the visual and eventually cleared to land on runway xxl. Conditions were VMC but windy with gusts. Our reference speed was 152 knots due to wind and weight. We had configured the plane to gear down and flaps 15 at this time. Between 1500 ft and 1000 ft AGL; we were cleared to land on runway xxr now due traffic still on the runway xxl. I was the flying pilot and started my turn for the new runway. The captain dialed in the new frequency for their ILS runway xxr for reference. Around 800 ft AGL; we discovered the configuration of the plane and the captain selected flaps 30 and we continued with no other events. After we landed; we couldn't believe we forgot the flaps. But with the runway change distraction and the high reference speed; it didn't click until we were below the 1000 ft AGL point. When we got to the gate; we discussed what happened and were in disbelief of each other that we didn't elect to go around per sops. Sops are clear and any event in the future should be complied with as stated.supplemental information from acn 778824: we were doing a visual approach to runway xxl at ZZZ. Tower switched us to runway xxr at about 1500 ft AGL due to traffic on the runway. Target speed was 152 knots due to winds at ZZZ. First officer was flying correct speed and ready to call for final flaps when tower switched us to runway xxr. I switched his localizer frequency for him so he would have glideslope information with the gusty winds. Just after the 1000 ft call; the airplane gave us the caution; 'too low flaps.' I selected flaps 30 and we landed. When we got to the gate; we discussed our mistake and were both surprised we could do something so stupid. We also realized we should have executed a go-around when we discovered our mistake. Double check everything when operating in a non standard environment (runway change and gusty winds). Checklist!

Original NASA ASRS Text

Title: B737 FLT CREW ON VISUAL APPROACH TO LEFT RWY IS SWITCHED TO RIGHT RWY BY TOWER AT 1500 FT. FLT CREW DISCOVERS LANDING FLAPS NOT SET AT 800 FT AGL AND LANDS AFTER SELECTING FLAPS 30.

Narrative: LANDING AT ZZZ; WE WERE CLEARED FOR THE VISUAL AND EVENTUALLY CLEARED TO LAND ON RWY XXL. CONDITIONS WERE VMC BUT WINDY WITH GUSTS. OUR REF SPEED WAS 152 KNOTS DUE TO WIND AND WEIGHT. WE HAD CONFIGURED THE PLANE TO GEAR DOWN AND FLAPS 15 AT THIS TIME. BETWEEN 1500 FT AND 1000 FT AGL; WE WERE CLEARED TO LAND ON RWY XXR NOW DUE TRAFFIC STILL ON THE RWY XXL. I WAS THE FLYING PILOT AND STARTED MY TURN FOR THE NEW RUNWAY. THE CAPTAIN DIALED IN THE NEW FREQUENCY FOR THEIR ILS RWY XXR FOR REFERENCE. AROUND 800 FT AGL; WE DISCOVERED THE CONFIGURATION OF THE PLANE AND THE CAPTAIN SELECTED FLAPS 30 AND WE CONTINUED WITH NO OTHER EVENTS. AFTER WE LANDED; WE COULDN'T BELIEVE WE FORGOT THE FLAPS. BUT WITH THE RUNWAY CHANGE DISTRACTION AND THE HIGH REF SPEED; IT DIDN'T CLICK UNTIL WE WERE BELOW THE 1000 FT AGL POINT. WHEN WE GOT TO THE GATE; WE DISCUSSED WHAT HAPPENED AND WERE IN DISBELIEF OF EACH OTHER THAT WE DIDN'T ELECT TO GO AROUND PER SOPS. SOPS ARE CLEAR AND ANY EVENT IN THE FUTURE SHOULD BE COMPLIED WITH AS STATED.SUPPLEMENTAL INFO FROM ACN 778824: WE WERE DOING A VISUAL APPROACH TO RWY XXL AT ZZZ. TOWER SWITCHED US TO RWY XXR AT ABOUT 1500 FT AGL DUE TO TRAFFIC ON THE RUNWAY. TARGET SPEED WAS 152 KNOTS DUE TO WINDS AT ZZZ. FO WAS FLYING CORRECT SPEED AND READY TO CALL FOR FINAL FLAPS WHEN TOWER SWITCHED US TO RWY XXR. I SWITCHED HIS LOC FREQUENCY FOR HIM SO HE WOULD HAVE GLIDESLOPE INFORMATION WITH THE GUSTY WINDS. JUST AFTER THE 1000 FT CALL; THE AIRPLANE GAVE US THE CAUTION; 'TOO LOW FLAPS.' I SELECTED FLAPS 30 AND WE LANDED. WHEN WE GOT TO THE GATE; WE DISCUSSED OUR MISTAKE AND WERE BOTH SURPRISED WE COULD DO SOMETHING SO STUPID. WE ALSO REALIZED WE SHOULD HAVE EXECUTED A GO-AROUND WHEN WE DISCOVERED OUR MISTAKE. DOUBLE CHECK EVERYTHING WHEN OPERATING IN A NON STANDARD ENVIRONMENT (RUNWAY CHANGE AND GUSTY WINDS). CHECKLIST!

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.

Attributes
ACN	779091
Time
Date	200803
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
Altitude	agl single value : 800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : zzz.tower
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 190 flight time type : 190
ASRS Report	779091
Events
Anomaly	non adherence : company policies other anomaly
Independent Detector	aircraft equipment : gpws
Resolutory Action	none taken : anomaly accepted
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance

B737 flight crew on visual approach to left runway is switched to right runway by tower at 1500 ft. Flight crew discovers landing flaps not set at 800 ft AGL and lands after selecting flaps 30.