Narrative:

Completing deice we were unable to open APU bleed air valve for engine starts. Company dispatched air cart and, upon completion of deicing the second time, we successfully started engines. The after start checklist was completed. Captain elected to keep flaps up (due to snow accumulation on txwys and light snow falling). Flaps are normally placed to 1 degree or 5 degrees at this point which is part of the first officer's after start flow. We did not complete this before takeoff checklist at this point because we were holding the flaps up. As we sat in line for takeoff, we discussed numerous reasons and probable causes for no APU bleed air available. When we were next for takeoff, the captain instructed me to tell the tower we needed 1 min on runway (to run engines up to 70 percent N1 for 1 min per aircraft manual) and with parking brakes set for me to go back in the cabin and check wings for contamination. As we taxied into position on the runway, I completed the last items of the before takeoff checklist (which we refer to as 'below the line'). I had not noticed at this point we had not completed the before takeoff checklist 'to the line.' this checklist is always done to the line long before reaching the hold short line. During wing contamination inspection, I still did not notice the flaps were 'up.' upon returning to my seat (my leg to fly) I strapped in and we were already cleared for takeoff. As the throttles were advanced (approximately 75 percent N1) takeoff warning horn sounded. Immediately selected flaps 5 degrees and captain elected to continue takeoff (10000 ft runway and snow packed). Horn silenced in approximately 6 seconds rolling about 2000 ft takeoff roll. Flaps green light observed shortly thereafter. Rotation delayed 25-30 KTS for concern. Climb out uneventful. Reasons: 1) first trip after 10 days vacation (first officer). 2) early wake-up. 3) break in routine -- first officer always places flaps 1 degree or 5 degrees during after start flow. 4) distracted with minor APU problem. 5) situational awareness. I was so focused on contamination check and being solely responsible for making that judgement call for the captain, I did not notice leading edge devices or flaps. If static run 70 percent N1 had required throttles to be advanced 1/4 inch more, the takeoff warning horn would've sounded during static engine run-up.

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Original NASA ASRS Text

Title: TKOF WARNING HORN SOUNDS AS TKOF PROC WITHOUT FLAPS ATTEMPTED.

Narrative: COMPLETING DEICE WE WERE UNABLE TO OPEN APU BLEED AIR VALVE FOR ENG STARTS. COMPANY DISPATCHED AIR CART AND, UPON COMPLETION OF DEICING THE SECOND TIME, WE SUCCESSFULLY STARTED ENGS. THE AFTER START CHKLIST WAS COMPLETED. CAPT ELECTED TO KEEP FLAPS UP (DUE TO SNOW ACCUMULATION ON TXWYS AND LIGHT SNOW FALLING). FLAPS ARE NORMALLY PLACED TO 1 DEG OR 5 DEGS AT THIS POINT WHICH IS PART OF THE FO'S AFTER START FLOW. WE DID NOT COMPLETE THIS BEFORE TKOF CHKLIST AT THIS POINT BECAUSE WE WERE HOLDING THE FLAPS UP. AS WE SAT IN LINE FOR TKOF, WE DISCUSSED NUMEROUS REASONS AND PROBABLE CAUSES FOR NO APU BLEED AIR AVAILABLE. WHEN WE WERE NEXT FOR TKOF, THE CAPT INSTRUCTED ME TO TELL THE TWR WE NEEDED 1 MIN ON RWY (TO RUN ENGS UP TO 70 PERCENT N1 FOR 1 MIN PER ACFT MANUAL) AND WITH PARKING BRAKES SET FOR ME TO GO BACK IN THE CABIN AND CHK WINGS FOR CONTAMINATION. AS WE TAXIED INTO POS ON THE RWY, I COMPLETED THE LAST ITEMS OF THE BEFORE TKOF CHKLIST (WHICH WE REFER TO AS 'BELOW THE LINE'). I HAD NOT NOTICED AT THIS POINT WE HAD NOT COMPLETED THE BEFORE TKOF CHKLIST 'TO THE LINE.' THIS CHKLIST IS ALWAYS DONE TO THE LINE LONG BEFORE REACHING THE HOLD SHORT LINE. DURING WING CONTAMINATION INSPECTION, I STILL DID NOT NOTICE THE FLAPS WERE 'UP.' UPON RETURNING TO MY SEAT (MY LEG TO FLY) I STRAPPED IN AND WE WERE ALREADY CLRED FOR TKOF. AS THE THROTTLES WERE ADVANCED (APPROX 75 PERCENT N1) TKOF WARNING HORN SOUNDED. IMMEDIATELY SELECTED FLAPS 5 DEGS AND CAPT ELECTED TO CONTINUE TKOF (10000 FT RWY AND SNOW PACKED). HORN SILENCED IN APPROX 6 SECONDS ROLLING ABOUT 2000 FT TKOF ROLL. FLAPS GREEN LIGHT OBSERVED SHORTLY THEREAFTER. ROTATION DELAYED 25-30 KTS FOR CONCERN. CLBOUT UNEVENTFUL. REASONS: 1) FIRST TRIP AFTER 10 DAYS VACATION (FO). 2) EARLY WAKE-UP. 3) BREAK IN ROUTINE -- FO ALWAYS PLACES FLAPS 1 DEG OR 5 DEGS DURING AFTER START FLOW. 4) DISTRACTED WITH MINOR APU PROB. 5) SITUATIONAL AWARENESS. I WAS SO FOCUSED ON CONTAMINATION CHK AND BEING SOLELY RESPONSIBLE FOR MAKING THAT JUDGEMENT CALL FOR THE CAPT, I DID NOT NOTICE LEADING EDGE DEVICES OR FLAPS. IF STATIC RUN 70 PERCENT N1 HAD REQUIRED THROTTLES TO BE ADVANCED 1/4 INCH MORE, THE TKOF WARNING HORN WOULD'VE SOUNDED DURING STATIC ENG RUN-UP.

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.