Narrative:

We were cleared the CLARE2 departure dfw. At approximately xa:00Z; ZFW inquired; 'are we proceeding to tekbe?' shortly after passing poten; it became evident that the FMC had dropped waypoint tekbe. A thorough route and legs check was completed at the gate prior to departure; no discrepancies found. ZFW simply reclred us direct to swb with no apparent conflicts. Interestingly; the controller then asked us about the departure as he had seen this happen several times before. Flight continued uneventfully.callback conversation with reporter revealed the following information: reporter restated his certainty about he and the first officer having verified the route waypoints during preflight. He indicated the air carrier automatically uploads flight plans during preflight. The reporter stated that the preferential runway with an associated departure is part of the upload and if the original runway is changed by the flight crew because of a clearance change during preflight; when the final closeout performance data is uploading during taxi out; the runway may default back to the original runway. Reporter stated that the flight crew would then have to change the FMC runway but may not again verify the departure waypoints that would have been deleted with the runway change.supplemental information from acn 685646: I was first officer/PF. Departed dfw runway 35L on CLARE2.swb. Route and legs had been checked between captain and first officer during CDU check prior to departure during before start checklist. All points checked. Have flown this trip exclusively since nov and am thoroughly familiar with this SID. Late in the climb; ATC asked if we were headed to tekbe. I was navigating to swb; but should have been headed towards tekbe; off to our 11 O'clock about 20 miles. I quickly realized for some reason that the route no longer contained the points; clare - poten - tekbe - swb; but instead had changed to clare direct swb. We told ATC we would correct over to tekbe; which I entered and flew towards. ATC mentioned that often departure control will clear flts direct to swb and maybe this was the case. Actually it was not the case. Two experienced guys (each with over 1000 in the aircraft); got complacent; I guess. The fault is mainly mine -- I should have had the light turned on illuminating the SID which was dark on my window; and should have down what I normally do and make sure the next point is in view on my RNAV display. Neither of us could recall making a route change after the legs check -- but we should have continued to check the RNAV progress. No word from ATC about any conflicts; no traffic was observed on the TCAS; and after all was sorted out; they cleared us downline direct to hrv.callback conversation with reporter revealed the following information: reporter stated that no change was made to the flight plan either manually or automatically after the route was checked on preflight by he and the captain. He stated this departure was one of the most trouble free he has flown and does this trip approximately 5 times per month. He has not seen this type of anomaly prior to this event.

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Original NASA ASRS Text

Title: A B777'S FMC PROGRAMMED FOR DFW'S CLARE2 DEP DROPPED WAYPOINTS ON THE RNAV DEP. THE CREW HAD VERIFIED THE WAYPOINTS PRIOR TO PUSHBACK.

Narrative: WE WERE CLRED THE CLARE2 DEP DFW. AT APPROX XA:00Z; ZFW INQUIRED; 'ARE WE PROCEEDING TO TEKBE?' SHORTLY AFTER PASSING POTEN; IT BECAME EVIDENT THAT THE FMC HAD DROPPED WAYPOINT TEKBE. A THOROUGH RTE AND LEGS CHK WAS COMPLETED AT THE GATE PRIOR TO DEP; NO DISCREPANCIES FOUND. ZFW SIMPLY RECLRED US DIRECT TO SWB WITH NO APPARENT CONFLICTS. INTERESTINGLY; THE CTLR THEN ASKED US ABOUT THE DEP AS HE HAD SEEN THIS HAPPEN SEVERAL TIMES BEFORE. FLT CONTINUED UNEVENTFULLY.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR RESTATED HIS CERTAINTY ABOUT HE AND THE FO HAVING VERIFIED THE RTE WAYPOINTS DURING PREFLT. HE INDICATED THE ACR AUTOMATICALLY UPLOADS FLT PLANS DURING PREFLT. THE RPTR STATED THAT THE PREFERENTIAL RWY WITH AN ASSOCIATED DEP IS PART OF THE UPLOAD AND IF THE ORIGINAL RWY IS CHANGED BY THE FLT CREW BECAUSE OF A CLRNC CHANGE DURING PREFLT; WHEN THE FINAL CLOSEOUT PERFORMANCE DATA IS UPLOADING DURING TAXI OUT; THE RWY MAY DEFAULT BACK TO THE ORIGINAL RWY. RPTR STATED THAT THE FLT CREW WOULD THEN HAVE TO CHANGE THE FMC RWY BUT MAY NOT AGAIN VERIFY THE DEP WAYPOINTS THAT WOULD HAVE BEEN DELETED WITH THE RWY CHANGE.SUPPLEMENTAL INFO FROM ACN 685646: I WAS FO/PF. DEPARTED DFW RWY 35L ON CLARE2.SWB. RTE AND LEGS HAD BEEN CHKED BETWEEN CAPT AND FO DURING CDU CHK PRIOR TO DEP DURING BEFORE START CHKLIST. ALL POINTS CHKED. HAVE FLOWN THIS TRIP EXCLUSIVELY SINCE NOV AND AM THOROUGHLY FAMILIAR WITH THIS SID. LATE IN THE CLB; ATC ASKED IF WE WERE HEADED TO TEKBE. I WAS NAVIGATING TO SWB; BUT SHOULD HAVE BEEN HEADED TOWARDS TEKBE; OFF TO OUR 11 O'CLOCK ABOUT 20 MILES. I QUICKLY REALIZED FOR SOME REASON THAT THE RTE NO LONGER CONTAINED THE POINTS; CLARE - POTEN - TEKBE - SWB; BUT INSTEAD HAD CHANGED TO CLARE DIRECT SWB. WE TOLD ATC WE WOULD CORRECT OVER TO TEKBE; WHICH I ENTERED AND FLEW TOWARDS. ATC MENTIONED THAT OFTEN DEP CTL WILL CLR FLTS DIRECT TO SWB AND MAYBE THIS WAS THE CASE. ACTUALLY IT WAS NOT THE CASE. TWO EXPERIENCED GUYS (EACH WITH OVER 1000 IN THE ACFT); GOT COMPLACENT; I GUESS. THE FAULT IS MAINLY MINE -- I SHOULD HAVE HAD THE LIGHT TURNED ON ILLUMINATING THE SID WHICH WAS DARK ON MY WINDOW; AND SHOULD HAVE DOWN WHAT I NORMALLY DO AND MAKE SURE THE NEXT POINT IS IN VIEW ON MY RNAV DISPLAY. NEITHER OF US COULD RECALL MAKING A RTE CHANGE AFTER THE LEGS CHK -- BUT WE SHOULD HAVE CONTINUED TO CHK THE RNAV PROGRESS. NO WORD FROM ATC ABOUT ANY CONFLICTS; NO TFC WAS OBSERVED ON THE TCAS; AND AFTER ALL WAS SORTED OUT; THEY CLRED US DOWNLINE DIRECT TO HRV.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT NO CHANGE WAS MADE TO THE FLT PLAN EITHER MANUALLY OR AUTOMATICALLY AFTER THE RTE WAS CHKED ON PREFLT BY HE AND THE CAPT. HE STATED THIS DEP WAS ONE OF THE MOST TROUBLE FREE HE HAS FLOWN AND DOES THIS TRIP APPROX 5 TIMES PER MONTH. HE HAS NOT SEEN THIS TYPE OF ANOMALY PRIOR TO THIS EVENT.

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