Narrative:

On a normal visual approach to abq runway 26 at approximately 50' left wing appeared to stall with a sharp left bank induced. Also, aircraft started to sink abnormally. Go around thrust was applied and wings leveled, simultaneously left main gear touched down. Nose was raised, right main and then left main touched down again. Throttles were closed and nose gear lowered to runway. Reverse thrust was applied. A normal rollout and taxi to gate ensued. Visual inspection by maintenance and crew produced no evidence of ground contact by propellers or tailskid, and g-forces were not sufficient to warrant a hard landing write-up. The approach was stabilized from 500' to 50'. On VASI glidepath, sink rate less than 900 FPM, airspeed stabilized at vref + 5 KTS. Engines were spun up and fuel flows stabilized at 4500 pph. Flaps were verified at 33 degrees and all slats indicated extended. No indication of control problems. Wind was reported as 260/6 on ATIS and light and variable by tower. No known convective activity in the area. At 50' the airspeed suddenly dropped to vref - 2, and the left wing simply stalled for no apparent reason. Why the left wing stalled at vref - 2 is a mystery. Callback conversation with reporter revealed the following: company thinks that the left flaps were not down. The only way they could duplicate the problem in the simulator was to fly the approach with left flaps retracted. This particular aircraft had another incident of flap trouble subsequent to this one and it was then determined that the #6 left flap could be in the up position and still indicate down on the flight engineer's panel. Airline operational procedure has been changed so that the second officer must see and confirm 14 green lights before the flight crew verifies that they have left flap indication. The reporter commented that he does not think they could have recovered from this stall if they had been very much higher, at say about 300'. The flight recorder confirmed that the airspeed was normal for the gross weight and altitude and there were no unusual g-forces.

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Original NASA ASRS Text

Title: ACR WDB EXPERIENCED LEFT WING STALL 50' AGL AT START OF FLAIR. LNDG COMPLETED.

Narrative: ON A NORMAL VISUAL APCH TO ABQ RWY 26 AT APPROX 50' L WING APPEARED TO STALL WITH A SHARP L BANK INDUCED. ALSO, ACFT STARTED TO SINK ABNORMALLY. GO AROUND THRUST WAS APPLIED AND WINGS LEVELED, SIMULTANEOUSLY LEFT MAIN GEAR TOUCHED DOWN. NOSE WAS RAISED, RIGHT MAIN AND THEN LEFT MAIN TOUCHED DOWN AGAIN. THROTTLES WERE CLOSED AND NOSE GEAR LOWERED TO RWY. REVERSE THRUST WAS APPLIED. A NORMAL ROLLOUT AND TAXI TO GATE ENSUED. VISUAL INSPECTION BY MAINT AND CREW PRODUCED NO EVIDENCE OF GND CONTACT BY PROPS OR TAILSKID, AND G-FORCES WERE NOT SUFFICIENT TO WARRANT A HARD LNDG WRITE-UP. THE APCH WAS STABILIZED FROM 500' TO 50'. ON VASI GLIDEPATH, SINK RATE LESS THAN 900 FPM, AIRSPD STABILIZED AT VREF + 5 KTS. ENGS WERE SPUN UP AND FUEL FLOWS STABILIZED AT 4500 PPH. FLAPS WERE VERIFIED AT 33 DEGS AND ALL SLATS INDICATED EXTENDED. NO INDICATION OF CONTROL PROBS. WIND WAS RPTED AS 260/6 ON ATIS AND LIGHT AND VARIABLE BY TWR. NO KNOWN CONVECTIVE ACTIVITY IN THE AREA. AT 50' THE AIRSPD SUDDENLY DROPPED TO VREF - 2, AND THE L WING SIMPLY STALLED FOR NO APPARENT REASON. WHY THE LEFT WING STALLED AT VREF - 2 IS A MYSTERY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: COMPANY THINKS THAT THE L FLAPS WERE NOT DOWN. THE ONLY WAY THEY COULD DUPLICATE THE PROB IN THE SIMULATOR WAS TO FLY THE APCH WITH L FLAPS RETRACTED. THIS PARTICULAR ACFT HAD ANOTHER INCIDENT OF FLAP TROUBLE SUBSEQUENT TO THIS ONE AND IT WAS THEN DETERMINED THAT THE #6 L FLAP COULD BE IN THE UP POS AND STILL INDICATE DOWN ON THE FE'S PANEL. AIRLINE OPERATIONAL PROC HAS BEEN CHANGED SO THAT THE S/O MUST SEE AND CONFIRM 14 GREEN LIGHTS BEFORE THE FLC VERIFIES THAT THEY HAVE LEFT FLAP INDICATION. THE RPTR COMMENTED THAT HE DOES NOT THINK THEY COULD HAVE RECOVERED FROM THIS STALL IF THEY HAD BEEN VERY MUCH HIGHER, AT SAY ABOUT 300'. THE FLT RECORDER CONFIRMED THAT THE AIRSPD WAS NORMAL FOR THE GROSS WT AND ALT AND THERE WERE NO UNUSUAL G-FORCES.

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