Narrative:

Memphis was landing on runway 36R. Approach control had us on a very high right downwind. The first officer as the PF called for flaps 1 degree. Approach said slow to 180 KTS, turn right heading 270 degrees, putting us a base leg, still high. First officer said flaps 5 degrees, and I selected it. Approach said turn right heading 330 degrees, cleared for the approach, slow to 170 degrees and hold that to the marker. First officer said flaps 15 degrees, gear down, landing checklist. Here's where the problem began. It was at this point, slowing through maybe 180 KTS that I noticed that the trailing edge flaps were stuck in an asymmetrically split position between 0 and 1 degree. The reason I'm writing this report is because at this point, we were about 15 or 20 KTS slower than the approved minimum maneuvering speed for that flap setting. We were both guilty of not noticing that after calling for flap extension, the flaps had not extended properly. I caught the slip and immediately told the first officer to accelerate back up to the clean maneuvering speed. Then I told approach that we had a little flap problem and would need to orbit somewhere to run a lengthy checklist and troubleshoot the problem. Approach then told us to turn right heading 090 degrees and maintain our altitude (which I think was about 3000 ft MSL at that point). The first officer was still flying, the autoplt was engaged, and when he twirled the autothrottle bug up to 220 KTS, it was sluggish to advance the throttles (they never advance right away). When the first officer twirled the heading bug over to 090 degrees, the bank limiter was in its normal position at 25 degrees, so that's the angle to which the airplane banked. I noticed that the autothrottles were still not advancing, so I shoved the power up, told the first officer that's what I was doing, so he wouldn't think that I was simply taking the airplane away from him, and I said 'speed' in a slightly warning tone of voice. The airplane started to accelerate. But because of the bank and the associated increase of the wing's angle of attack and G force, this combination put us at the stick shaker alpha, and we got a little burst of it for maybe 1 second. We had already been correcting before the stick shaker, but to move things along a little faster, I took the airplane just long enough to simultaneously push the nose down (so we were still on autoplt, but this took us out of heading and altitude hold modes and into the control wheel steering mode), push to power up even more, and roll level. With the aircraft back at the clean minimum maneuvering speed, we ran the 'trailing edge flaps malfunction' checklist. With alternate flaps switch armed, I briefly held down the alternate flap switch to achieve led full extension, and the trailing edge asymmetry disappeared. With the airplane properly configured for a flaps 15 degree landing, I took control of the airplane and we landed without further incident. Before landing, I informed and briefed all the appropriate parties, including the flight attendants, the passenger, the company, maintenance, called for the emergency vehicles as a precaution.

Related reports:

Google
 

Original NASA ASRS Text

Title: A B737-500 FLC HAD THE AUTOPLT ENGAGED WITH A TRAILING EDGE FLAP PROB. USE OF THE AUTOPLT DURING A GAR RESULTED IN A STICK SHAKER WARNING.

Narrative: MEMPHIS WAS LNDG ON RWY 36R. APCH CTL HAD US ON A VERY HIGH R DOWNWIND. THE FO AS THE PF CALLED FOR FLAPS 1 DEG. APCH SAID SLOW TO 180 KTS, TURN R HDG 270 DEGS, PUTTING US A BASE LEG, STILL HIGH. FO SAID FLAPS 5 DEGS, AND I SELECTED IT. APCH SAID TURN R HDG 330 DEGS, CLRED FOR THE APCH, SLOW TO 170 DEGS AND HOLD THAT TO THE MARKER. FO SAID FLAPS 15 DEGS, GEAR DOWN, LNDG CHKLIST. HERE'S WHERE THE PROB BEGAN. IT WAS AT THIS POINT, SLOWING THROUGH MAYBE 180 KTS THAT I NOTICED THAT THE TRAILING EDGE FLAPS WERE STUCK IN AN ASYMMETRICALLY SPLIT POS BTWN 0 AND 1 DEG. THE REASON I'M WRITING THIS RPT IS BECAUSE AT THIS POINT, WE WERE ABOUT 15 OR 20 KTS SLOWER THAN THE APPROVED MINIMUM MANEUVERING SPD FOR THAT FLAP SETTING. WE WERE BOTH GUILTY OF NOT NOTICING THAT AFTER CALLING FOR FLAP EXTENSION, THE FLAPS HAD NOT EXTENDED PROPERLY. I CAUGHT THE SLIP AND IMMEDIATELY TOLD THE FO TO ACCELERATE BACK UP TO THE CLEAN MANEUVERING SPD. THEN I TOLD APCH THAT WE HAD A LITTLE FLAP PROB AND WOULD NEED TO ORBIT SOMEWHERE TO RUN A LENGTHY CHKLIST AND TROUBLESHOOT THE PROB. APCH THEN TOLD US TO TURN R HDG 090 DEGS AND MAINTAIN OUR ALT (WHICH I THINK WAS ABOUT 3000 FT MSL AT THAT POINT). THE FO WAS STILL FLYING, THE AUTOPLT WAS ENGAGED, AND WHEN HE TWIRLED THE AUTOTHROTTLE BUG UP TO 220 KTS, IT WAS SLUGGISH TO ADVANCE THE THROTTLES (THEY NEVER ADVANCE RIGHT AWAY). WHEN THE FO TWIRLED THE HDG BUG OVER TO 090 DEGS, THE BANK LIMITER WAS IN ITS NORMAL POS AT 25 DEGS, SO THAT'S THE ANGLE TO WHICH THE AIRPLANE BANKED. I NOTICED THAT THE AUTOTHROTTLES WERE STILL NOT ADVANCING, SO I SHOVED THE PWR UP, TOLD THE FO THAT'S WHAT I WAS DOING, SO HE WOULDN'T THINK THAT I WAS SIMPLY TAKING THE AIRPLANE AWAY FROM HIM, AND I SAID 'SPD' IN A SLIGHTLY WARNING TONE OF VOICE. THE AIRPLANE STARTED TO ACCELERATE. BUT BECAUSE OF THE BANK AND THE ASSOCIATED INCREASE OF THE WING'S ANGLE OF ATTACK AND G FORCE, THIS COMBINATION PUT US AT THE STICK SHAKER ALPHA, AND WE GOT A LITTLE BURST OF IT FOR MAYBE 1 SECOND. WE HAD ALREADY BEEN CORRECTING BEFORE THE STICK SHAKER, BUT TO MOVE THINGS ALONG A LITTLE FASTER, I TOOK THE AIRPLANE JUST LONG ENOUGH TO SIMULTANEOUSLY PUSH THE NOSE DOWN (SO WE WERE STILL ON AUTOPLT, BUT THIS TOOK US OUT OF HDG AND ALT HOLD MODES AND INTO THE CTL WHEEL STEERING MODE), PUSH TO PWR UP EVEN MORE, AND ROLL LEVEL. WITH THE ACFT BACK AT THE CLEAN MINIMUM MANEUVERING SPD, WE RAN THE 'TRAILING EDGE FLAPS MALFUNCTION' CHKLIST. WITH ALTERNATE FLAPS SWITCH ARMED, I BRIEFLY HELD DOWN THE ALTERNATE FLAP SWITCH TO ACHIEVE LED FULL EXTENSION, AND THE TRAILING EDGE ASYMMETRY DISAPPEARED. WITH THE AIRPLANE PROPERLY CONFIGURED FOR A FLAPS 15 DEG LNDG, I TOOK CTL OF THE AIRPLANE AND WE LANDED WITHOUT FURTHER INCIDENT. BEFORE LNDG, I INFORMED AND BRIEFED ALL THE APPROPRIATE PARTIES, INCLUDING THE FLT ATTENDANTS, THE PAX, THE COMPANY, MAINT, CALLED FOR THE EMER VEHICLES AS A PRECAUTION.

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.