Narrative:

The first officer was the PF; I was in the jumpseat acting as relief pilot. We were given a descent from 7000 ft to 4000 ft followed immediately by a traffic call; a turn to 180 degrees (base) and a speed reduction to 180 KIAS. We were already configured at flaps 1 degree and at 210 KIAS with the autoplt engaged. While turning to base; looking for traffic and setting 180 KIAS in the MCP IAS/mach window; the aircraft descended through the bottom of a cloud layer at approximately 6000 ft MSL. There must have been an increase in wind; because the airspeed instantaneously increased to 262 KIAS; causing a flap overspeed message on the EICAS and an aural alert. The captain elected to retract the flaps to zero and we then received a leading edge slat disagree EICAS message and leading edge slat caution light. We leveled at 4000 ft; advised ATC that we had a problem and elected to continue the approach; as we were about 10 NM outside the marker. The captain told the first officer to remain flying and he (captain) and I began running the leading edge slat disagree checklist. As per the checklist; we placed the leading edge alternate flaps switch to altn and tried to lower the flaps to 20 degrees for landing using the altn flaps switch (the leading edge caution light had gone out after we selected altn with the leading edge altn flap switch). We were surprised by the fact that the flaps were not extending as we expected them to and we began a discussion as to why this might be happening. The first officer must have allowed himself to become involved in our discussion; because the aircraft slowed below clean speed (the first officer thought we were lowering flaps to 1 degree and was slowing the aircraft to the reference speed for that confign) and we received a stall indication (stick shaker and horn). The captain assumed control of the aircraft; recovered; and initiated a go around. We followed ATC instructions for a turn to downwind and requested an extended downwind to continue to run our abnormal checklist. We did declare an emergency because we anticipated landing with reduced flaps and higher approach speed; but I do not recall exactly when the declaration was made. Now the captain is the PF and the first officer and myself have been tasked with running the abnormal checklist. We decided to go back to the beginning of the leading edge disagree checklist and start it again. This time when we placed the leading edge alternate flaps switch to altn; the leading edge caution light remained illuminated. As per the checklist; the leading edge altn flaps switch was placed off and we were sent to the leading edge slat asymmetry checklist. Now the flaps and slats extended to 20 degrees and we accomplished our approach and landing with flaps 20 degrees and vref 30+30. Our landing and subsequent taxi to the gate were normal and our emergency was terminated by the captain. Lessons learned: the PF should do only that and not get involved with running the checklists (abnormal). The format of the checklists caused confusion in the heat of battle. Some of the 'if; then' bullets seem to lead in unexpected directions or leave uncertainty as to the proper direction to pursue. Supplemental information from acn 779681: ATC clearance: descend to 4000 ft MSL maintain 220 KTS. Right autoplt in cmd; flight level change; autothrottle in speed mode 220 KTS in MCP speed window; flaps up; speed brakes extended. ATC revised speed to 210 KTS. After setting 210 in the speed window I called for flaps 1 degree. Captain set flaps to 1 degree. Passing through approximately 4500 ft MSL we descended below a scattered cloud layer. I noticed that the airspeed began to increase. ATC called for a left turn to 180 degrees; look for traffic to follow for a visual approach. The captain looked for the traffic as I set 180 degrees on the heading bug. As the aircraft leveled at 4000 ft; the airspeed was still increasing towards 240 KTS. While the captain was busy looking for traffic I raised the flap handle to avoid a flap overspeed. Airspeed peaked at approximately 260 KTS. During flap retraction the leading edge slat disagree EICAS message illuminated. As the captain and relief pilot began the non-normal checklist I continued flying the aircraft. ATC cleared us to descend to 3500 ft and to interceptthe localizer. It became evident that we could not complete the necessary checklists in time to accomplish a safe landing. The captain elected to execute a missed approach and took control on the aircraft. At this point it appeared that we might not be able to extend the trailing edge flaps and might need to execute a no flap landing. I declared an emergency and requested vectors to the long runway. Once established on downwind the relief pilot and I accomplished the leading edge slat disagree checklist. The flaps extended to 20 degrees and the captain landed without further incident.

Related reports:

Google
 

Original NASA ASRS Text

Title: B767 FLT CREW REPORTS FLAP OVERSPEED ON APPROACH DUE TO WIND SHEAR AND LE FLAP DISAGREE RESULTING IN FLAP 20 LANDING.

Narrative: THE FO WAS THE PF; I WAS IN THE JUMPSEAT ACTING AS RELIEF PLT. WE WERE GIVEN A DSCNT FROM 7000 FT TO 4000 FT FOLLOWED IMMEDIATELY BY A TFC CALL; A TURN TO 180 DEGS (BASE) AND A SPD REDUCTION TO 180 KIAS. WE WERE ALREADY CONFIGURED AT FLAPS 1 DEG AND AT 210 KIAS WITH THE AUTOPLT ENGAGED. WHILE TURNING TO BASE; LOOKING FOR TFC AND SETTING 180 KIAS IN THE MCP IAS/MACH WINDOW; THE ACFT DSNDED THROUGH THE BOTTOM OF A CLOUD LAYER AT APPROX 6000 FT MSL. THERE MUST HAVE BEEN AN INCREASE IN WIND; BECAUSE THE AIRSPD INSTANTANEOUSLY INCREASED TO 262 KIAS; CAUSING A FLAP OVERSPEED MESSAGE ON THE EICAS AND AN AURAL ALERT. THE CAPT ELECTED TO RETRACT THE FLAPS TO ZERO AND WE THEN RECEIVED A LEADING EDGE SLAT DISAGREE EICAS MESSAGE AND LEADING EDGE SLAT CAUTION LIGHT. WE LEVELED AT 4000 FT; ADVISED ATC THAT WE HAD A PROB AND ELECTED TO CONTINUE THE APCH; AS WE WERE ABOUT 10 NM OUTSIDE THE MARKER. THE CAPT TOLD THE FO TO REMAIN FLYING AND HE (CAPT) AND I BEGAN RUNNING THE LEADING EDGE SLAT DISAGREE CHKLIST. AS PER THE CHKLIST; WE PLACED THE LEADING EDGE ALTERNATE FLAPS SWITCH TO ALTN AND TRIED TO LOWER THE FLAPS TO 20 DEGS FOR LNDG USING THE ALTN FLAPS SWITCH (THE LEADING EDGE CAUTION LIGHT HAD GONE OUT AFTER WE SELECTED ALTN WITH THE LEADING EDGE ALTN FLAP SWITCH). WE WERE SURPRISED BY THE FACT THAT THE FLAPS WERE NOT EXTENDING AS WE EXPECTED THEM TO AND WE BEGAN A DISCUSSION AS TO WHY THIS MIGHT BE HAPPENING. THE FO MUST HAVE ALLOWED HIMSELF TO BECOME INVOLVED IN OUR DISCUSSION; BECAUSE THE ACFT SLOWED BELOW CLEAN SPD (THE FO THOUGHT WE WERE LOWERING FLAPS TO 1 DEG AND WAS SLOWING THE ACFT TO THE REF SPD FOR THAT CONFIGN) AND WE RECEIVED A STALL INDICATION (STICK SHAKER AND HORN). THE CAPT ASSUMED CTL OF THE ACFT; RECOVERED; AND INITIATED A GAR. WE FOLLOWED ATC INSTRUCTIONS FOR A TURN TO DOWNWIND AND REQUESTED AN EXTENDED DOWNWIND TO CONTINUE TO RUN OUR ABNORMAL CHKLIST. WE DID DECLARE AN EMER BECAUSE WE ANTICIPATED LNDG WITH REDUCED FLAPS AND HIGHER APCH SPD; BUT I DO NOT RECALL EXACTLY WHEN THE DECLARATION WAS MADE. NOW THE CAPT IS THE PF AND THE FO AND MYSELF HAVE BEEN TASKED WITH RUNNING THE ABNORMAL CHKLIST. WE DECIDED TO GO BACK TO THE BEGINNING OF THE LEADING EDGE DISAGREE CHKLIST AND START IT AGAIN. THIS TIME WHEN WE PLACED THE LEADING EDGE ALTERNATE FLAPS SWITCH TO ALTN; THE LEADING EDGE CAUTION LIGHT REMAINED ILLUMINATED. AS PER THE CHKLIST; THE LEADING EDGE ALTN FLAPS SWITCH WAS PLACED OFF AND WE WERE SENT TO THE LEADING EDGE SLAT ASYMMETRY CHKLIST. NOW THE FLAPS AND SLATS EXTENDED TO 20 DEGS AND WE ACCOMPLISHED OUR APCH AND LNDG WITH FLAPS 20 DEGS AND VREF 30+30. OUR LNDG AND SUBSEQUENT TAXI TO THE GATE WERE NORMAL AND OUR EMER WAS TERMINATED BY THE CAPT. LESSONS LEARNED: THE PF SHOULD DO ONLY THAT AND NOT GET INVOLVED WITH RUNNING THE CHKLISTS (ABNORMAL). THE FORMAT OF THE CHKLISTS CAUSED CONFUSION IN THE HEAT OF BATTLE. SOME OF THE 'IF; THEN' BULLETS SEEM TO LEAD IN UNEXPECTED DIRECTIONS OR LEAVE UNCERTAINTY AS TO THE PROPER DIRECTION TO PURSUE. SUPPLEMENTAL INFO FROM ACN 779681: ATC CLRNC: DSND TO 4000 FT MSL MAINTAIN 220 KTS. R AUTOPLT IN CMD; FLT LEVEL CHANGE; AUTOTHROTTLE IN SPD MODE 220 KTS IN MCP SPD WINDOW; FLAPS UP; SPD BRAKES EXTENDED. ATC REVISED SPD TO 210 KTS. AFTER SETTING 210 IN THE SPD WINDOW I CALLED FOR FLAPS 1 DEG. CAPT SET FLAPS TO 1 DEG. PASSING THROUGH APPROX 4500 FT MSL WE DSNDED BELOW A SCATTERED CLOUD LAYER. I NOTICED THAT THE AIRSPD BEGAN TO INCREASE. ATC CALLED FOR A L TURN TO 180 DEGS; LOOK FOR TFC TO FOLLOW FOR A VISUAL APCH. THE CAPT LOOKED FOR THE TFC AS I SET 180 DEGS ON THE HDG BUG. AS THE ACFT LEVELED AT 4000 FT; THE AIRSPD WAS STILL INCREASING TOWARDS 240 KTS. WHILE THE CAPT WAS BUSY LOOKING FOR TFC I RAISED THE FLAP HANDLE TO AVOID A FLAP OVERSPEED. AIRSPD PEAKED AT APPROX 260 KTS. DURING FLAP RETRACTION THE LEADING EDGE SLAT DISAGREE EICAS MESSAGE ILLUMINATED. AS THE CAPT AND RELIEF PLT BEGAN THE NON-NORMAL CHKLIST I CONTINUED FLYING THE ACFT. ATC CLRED US TO DSND TO 3500 FT AND TO INTERCEPTTHE LOC. IT BECAME EVIDENT THAT WE COULD NOT COMPLETE THE NECESSARY CHKLISTS IN TIME TO ACCOMPLISH A SAFE LNDG. THE CAPT ELECTED TO EXECUTE A MISSED APCH AND TOOK CTL ON THE ACFT. AT THIS POINT IT APPEARED THAT WE MIGHT NOT BE ABLE TO EXTEND THE TRAILING EDGE FLAPS AND MIGHT NEED TO EXECUTE A NO FLAP LNDG. I DECLARED AN EMER AND REQUESTED VECTORS TO THE LONG RWY. ONCE ESTABLISHED ON DOWNWIND THE RELIEF PLT AND I ACCOMPLISHED THE LEADING EDGE SLAT DISAGREE CHKLIST. THE FLAPS EXTENDED TO 20 DEGS AND THE CAPT LANDED WITHOUT FURTHER INCIDENT.

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.