|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1801 To 2400|
|Locale Reference||airport : tpa|
|Altitude||msl bound lower : 2000|
msl bound upper : 3000
|Controlling Facilities||tracon : tpa|
|Operator||common carrier : air carrier|
|Make Model Name||Widebody, Low Wing, 2 Turbojet Eng|
|Navigation In Use||Other |
|Flight Phase||descent : approach|
|Route In Use||arrival other|
|Affiliation||company : air carrier|
|Function||flight crew : first officer|
|Qualification||pilot : atp|
pilot : flight engineer
pilot : cfi
|Experience||flight time last 90 days : 150|
flight time total : 5200
flight time type : 52
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : atp|
|Experience||flight time type : 52|
|Anomaly||aircraft equipment problem : less severe|
|Independent Detector||other flight crewa|
|Resolutory Action||flight crew : overcame equipment problem|
|Air Traffic Incident||other|
All proceeded as expected until the captain commanded flaps past 5. As soon as the flap position indicator showed just past 1, the flaps seemed to lock out and the EICAS status message came on. It informed us that the trailing edge flaps asymmetry had occurred. The captain then made a go around. I informed the tower that we were discontinuing the approach. I ran through the after takeoff checklist, and then contacted departure (approach) control. We were assigned an altitude of 3000' and vectors within the local area. Upon the captain's command I ran the trailing edge flap asymmetry checklist. We then lowered the flaps through the alternate means, following the checklist to the letter. Subsequently, we asked and were assigned another approach to the airport. The captain asked me to request rescue equipment to be standing by for our landing. I did and the controller asked us for the fuel quantity and number of passenger. I provided both. Our landing was west/O incident. The captain flew the aircraft and T/D was made with flaps 20 and the appropriate vref for flaps 20, as per the applicable checklist. We cancelled the request for equipment after roll out, and we taxied to the gate under our own power after exiting the runway. The significance of this occurrence was not, I feel, attributable to the occurrence itself or how we handled it. We were well trained by aircraft mfr to deal with this type of situation. The significance comes from what might have caused this problem to begin with. The following morning when we returned to the aircraft to continue our trip series, the maintenance foreman informed us that the maintenance department had not found any problems with the system related to the flap operation. Furthermore, he indicated that he had only been able to duplicate our problem by switching the alternate flap switch to the up position from the norm position where it is usually kept, and then by attempting to operate the flaps using the normal means, (ie, with the handle and not by the alternate switch). He said that doing this caused the trailing edge flaps to lock out at just past one when in the landing confign (similar to what had happened to us). He added that, while on the ground in the takeoff mode, it would still be possible to get flaps to 5. (We had used flaps 5 for takeoff at our origin the preceding evening. I am absolutely certain that the flap position indicator was showing 5 at takeoff.) I am almost as certain that the alternate flap switch was in norm and not in up as we taxied for takeoff the preceding evening. Still, I can only confirm that this is part of the normal cabin set up I am accustomed to using. I cannot visualize the position of that dial as I can the flap position indicator. This switch should always be in norm and not in up unless the alternate flaps are in use. The only way that this switch could have been in up is if the preceding flight crew or the maintenance people who had worked on the aircraft after the (preceding) crew had departed switched the alternate flaps on and then neglected to switch it off. If this had occurred, and if we had failed to catch the incorrect position on our before start switch position set up, we may have helped to create our own problem. Keep in mind that all of this is conjecture. To the best of my knowledge that switch was in the normal position until I moved it out of same during the abnormal procedure. The trailing edge flap asymmetry procedure is a relatively short but intricate procedure. Still, if we had not followed it correctly, or if the alternate flap mechanism had failed to operate, we might not have been able to lower the flaps for landing. That would have presented enormous problems. It is my strong belief that boeing needs to install an on light to indicate whenever the alternate flap switch is on or the system is energized. Absent this, there should at least be a lead in note within the trailing edge flap asymmetry checklist to alert the crew that their problem might come from the rotary dial being in the up rather than the normal position. If either of these conditions had existed and if the switch was in the up position--I do not believe it was--I might have been spared these observations now. Aircraft mfr might say that this was a simple mistake for a flight crew to make. Keep in mind, however, that there are hundreds of lights and switches for us to keep track of. I humbly suggest that you give this matter some attention. There are 2 other items I will touch on briefly. The first is the matter of the speed-break/ground spoiler armed light on the widebody transport. Unlike the medium large transport, there isn't one. On the widebody transport landing checklist, more than once the captain has called the speed-break armed, only to see it fail to deploy automatically upon landing. (The ground spoilers will deploy automatically upon landing only if the handle is in the armed position. If the handle is not in the armed position, the spoilers will deploy automatically only when reverse thrust is actuated. In this latter situation, valuable stopping time and distance may be wasted.) a speed-break/ground spoiler armed light on the widebody transport would not guarantee that the spoilers would deploy on landing, but it might at least assure the crew that the mechanism was either definitely armed or definitely malfunctioning. Finally, on the widebody transport, there is no altitude alert bell 900' before reaching the altitude which has been set on the MCP. Ostensibly, this is for maintenance of the quiet cockpit concept. I can definitely not speak as an authority on human factors, but I would feel a log more secure if, like the medium large transport, the widebody transport had a single aural tone to accompany the light which now appears between 900 and 300' above/below the MCP altitude. Callback conversation with reporter revealed the following: narrative should be corrected to state EICAS message was that a trailing edge flaps disagree occurred, not a trailing edge flaps asymmetry. Reporter pointed out that their manual doesn't provide flight crew prerogative of returning switches and handles to original position and recycling alternate switches to normal and then starting procedure over to see if lockout has been removed. Feels that might not be in there so mfr would not have to acknowledge possible problem to FAA. Reporter also stated that other items are personal opinions and once he is used to new aircraft probably will not be a problem.
Original NASA ASRS Text
Title: ACR WDB INCURRED TRAILING EDGE FLAP DISAGREE MSG AND LOCKOUT, EXECUTED MISSED APCH, EXTENDED FLAPS PER ABNORMAL PROC AND LNDG. REPORTER ALSO COMPLAINS ABOUT WARNING ALERTING SYSTEM ON ALT ALERT AND SPOILER SYSTEM INDICATION.
Narrative: ALL PROCEEDED AS EXPECTED UNTIL THE CAPT COMMANDED FLAPS PAST 5. AS SOON AS THE FLAP POS INDICATOR SHOWED JUST PAST 1, THE FLAPS SEEMED TO LOCK OUT AND THE EICAS STATUS MESSAGE CAME ON. IT INFORMED US THAT THE TRAILING EDGE FLAPS ASYMMETRY HAD OCCURRED. THE CAPT THEN MADE A GO AROUND. I INFORMED THE TWR THAT WE WERE DISCONTINUING THE APCH. I RAN THROUGH THE AFTER TKOF CHKLIST, AND THEN CONTACTED DEP (APCH) CTL. WE WERE ASSIGNED AN ALT OF 3000' AND VECTORS WITHIN THE LCL AREA. UPON THE CAPT'S COMMAND I RAN THE TRAILING EDGE FLAP ASYMMETRY CHKLIST. WE THEN LOWERED THE FLAPS THROUGH THE ALTERNATE MEANS, FOLLOWING THE CHKLIST TO THE LETTER. SUBSEQUENTLY, WE ASKED AND WERE ASSIGNED ANOTHER APCH TO THE ARPT. THE CAPT ASKED ME TO REQUEST RESCUE EQUIP TO BE STANDING BY FOR OUR LNDG. I DID AND THE CTLR ASKED US FOR THE FUEL QUANTITY AND NUMBER OF PAX. I PROVIDED BOTH. OUR LNDG WAS W/O INCIDENT. THE CAPT FLEW THE ACFT AND T/D WAS MADE WITH FLAPS 20 AND THE APPROPRIATE VREF FOR FLAPS 20, AS PER THE APPLICABLE CHKLIST. WE CANCELLED THE REQUEST FOR EQUIP AFTER ROLL OUT, AND WE TAXIED TO THE GATE UNDER OUR OWN PWR AFTER EXITING THE RWY. THE SIGNIFICANCE OF THIS OCCURRENCE WAS NOT, I FEEL, ATTRIBUTABLE TO THE OCCURRENCE ITSELF OR HOW WE HANDLED IT. WE WERE WELL TRAINED BY ACFT MFR TO DEAL WITH THIS TYPE OF SITUATION. THE SIGNIFICANCE COMES FROM WHAT MIGHT HAVE CAUSED THIS PROB TO BEGIN WITH. THE FOLLOWING MORNING WHEN WE RETURNED TO THE ACFT TO CONTINUE OUR TRIP SERIES, THE MAINT FOREMAN INFORMED US THAT THE MAINT DEPT HAD NOT FOUND ANY PROBS WITH THE SYS RELATED TO THE FLAP OPERATION. FURTHERMORE, HE INDICATED THAT HE HAD ONLY BEEN ABLE TO DUPLICATE OUR PROB BY SWITCHING THE ALTERNATE FLAP SWITCH TO THE UP POS FROM THE NORM POS WHERE IT IS USUALLY KEPT, AND THEN BY ATTEMPTING TO OPERATE THE FLAPS USING THE NORMAL MEANS, (IE, WITH THE HANDLE AND NOT BY THE ALTERNATE SWITCH). HE SAID THAT DOING THIS CAUSED THE TRAILING EDGE FLAPS TO LOCK OUT AT JUST PAST ONE WHEN IN THE LNDG CONFIGN (SIMILAR TO WHAT HAD HAPPENED TO US). HE ADDED THAT, WHILE ON THE GND IN THE TKOF MODE, IT WOULD STILL BE POSSIBLE TO GET FLAPS TO 5. (WE HAD USED FLAPS 5 FOR TKOF AT OUR ORIGIN THE PRECEDING EVENING. I AM ABSOLUTELY CERTAIN THAT THE FLAP POS INDICATOR WAS SHOWING 5 AT TKOF.) I AM ALMOST AS CERTAIN THAT THE ALTERNATE FLAP SWITCH WAS IN NORM AND NOT IN UP AS WE TAXIED FOR TKOF THE PRECEDING EVENING. STILL, I CAN ONLY CONFIRM THAT THIS IS PART OF THE NORMAL CABIN SET UP I AM ACCUSTOMED TO USING. I CANNOT VISUALIZE THE POS OF THAT DIAL AS I CAN THE FLAP POS INDICATOR. THIS SWITCH SHOULD ALWAYS BE IN NORM AND NOT IN UP UNLESS THE ALTERNATE FLAPS ARE IN USE. THE ONLY WAY THAT THIS SWITCH COULD HAVE BEEN IN UP IS IF THE PRECEDING FLT CREW OR THE MAINT PEOPLE WHO HAD WORKED ON THE ACFT AFTER THE (PRECEDING) CREW HAD DEPARTED SWITCHED THE ALTERNATE FLAPS ON AND THEN NEGLECTED TO SWITCH IT OFF. IF THIS HAD OCCURRED, AND IF WE HAD FAILED TO CATCH THE INCORRECT POS ON OUR BEFORE START SWITCH POS SET UP, WE MAY HAVE HELPED TO CREATE OUR OWN PROB. KEEP IN MIND THAT ALL OF THIS IS CONJECTURE. TO THE BEST OF MY KNOWLEDGE THAT SWITCH WAS IN THE NORMAL POS UNTIL I MOVED IT OUT OF SAME DURING THE ABNORMAL PROC. THE TRAILING EDGE FLAP ASYMMETRY PROC IS A RELATIVELY SHORT BUT INTRICATE PROC. STILL, IF WE HAD NOT FOLLOWED IT CORRECTLY, OR IF THE ALTERNATE FLAP MECHANISM HAD FAILED TO OPERATE, WE MIGHT NOT HAVE BEEN ABLE TO LOWER THE FLAPS FOR LNDG. THAT WOULD HAVE PRESENTED ENORMOUS PROBS. IT IS MY STRONG BELIEF THAT BOEING NEEDS TO INSTALL AN ON LIGHT TO INDICATE WHENEVER THE ALTERNATE FLAP SWITCH IS ON OR THE SYS IS ENERGIZED. ABSENT THIS, THERE SHOULD AT LEAST BE A LEAD IN NOTE WITHIN THE TRAILING EDGE FLAP ASYMMETRY CHKLIST TO ALERT THE CREW THAT THEIR PROB MIGHT COME FROM THE ROTARY DIAL BEING IN THE UP RATHER THAN THE NORMAL POS. IF EITHER OF THESE CONDITIONS HAD EXISTED AND IF THE SWITCH WAS IN THE UP POS--I DO NOT BELIEVE IT WAS--I MIGHT HAVE BEEN SPARED THESE OBSERVATIONS NOW. ACFT MFR MIGHT SAY THAT THIS WAS A SIMPLE MISTAKE FOR A FLT CREW TO MAKE. KEEP IN MIND, HOWEVER, THAT THERE ARE HUNDREDS OF LIGHTS AND SWITCHES FOR US TO KEEP TRACK OF. I HUMBLY SUGGEST THAT YOU GIVE THIS MATTER SOME ATTN. THERE ARE 2 OTHER ITEMS I WILL TOUCH ON BRIEFLY. THE FIRST IS THE MATTER OF THE SPD-BREAK/GND SPOILER ARMED LIGHT ON THE WDB. UNLIKE THE MLG, THERE ISN'T ONE. ON THE WDB LNDG CHKLIST, MORE THAN ONCE THE CAPT HAS CALLED THE SPD-BREAK ARMED, ONLY TO SEE IT FAIL TO DEPLOY AUTOMATICALLY UPON LNDG. (THE GND SPOILERS WILL DEPLOY AUTOMATICALLY UPON LNDG ONLY IF THE HANDLE IS IN THE ARMED POS. IF THE HANDLE IS NOT IN THE ARMED POS, THE SPOILERS WILL DEPLOY AUTOMATICALLY ONLY WHEN REVERSE THRUST IS ACTUATED. IN THIS LATTER SITUATION, VALUABLE STOPPING TIME AND DISTANCE MAY BE WASTED.) A SPD-BREAK/GND SPOILER ARMED LIGHT ON THE WDB WOULD NOT GUARANTEE THAT THE SPOILERS WOULD DEPLOY ON LNDG, BUT IT MIGHT AT LEAST ASSURE THE CREW THAT THE MECHANISM WAS EITHER DEFINITELY ARMED OR DEFINITELY MALFUNCTIONING. FINALLY, ON THE WDB, THERE IS NO ALT ALERT BELL 900' BEFORE REACHING THE ALT WHICH HAS BEEN SET ON THE MCP. OSTENSIBLY, THIS IS FOR MAINT OF THE QUIET COCKPIT CONCEPT. I CAN DEFINITELY NOT SPEAK AS AN AUTHORITY ON HUMAN FACTORS, BUT I WOULD FEEL A LOG MORE SECURE IF, LIKE THE MLG, THE WDB HAD A SINGLE AURAL TONE TO ACCOMPANY THE LIGHT WHICH NOW APPEARS BTWN 900 AND 300' ABOVE/BELOW THE MCP ALT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: NARRATIVE SHOULD BE CORRECTED TO STATE EICAS MSG WAS THAT A TRAILING EDGE FLAPS DISAGREE OCCURRED, NOT A TRAILING EDGE FLAPS ASYMMETRY. RPTR POINTED OUT THAT THEIR MANUAL DOESN'T PROVIDE FLT CREW PREROGATIVE OF RETURNING SWITCHES AND HANDLES TO ORIGINAL POS AND RECYCLING ALTERNATE SWITCHES TO NORMAL AND THEN STARTING PROC OVER TO SEE IF LOCKOUT HAS BEEN REMOVED. FEELS THAT MIGHT NOT BE IN THERE SO MFR WOULD NOT HAVE TO ACKNOWLEDGE POSSIBLE PROB TO FAA. RPTR ALSO STATED THAT OTHER ITEMS ARE PERSONAL OPINIONS AND ONCE HE IS USED TO NEW ACFT PROBABLY WILL NOT BE A PROB.
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.