Narrative:

Did not set flaps on after start checklist. Was rushed for takeoff by other aircraft on final. Cleared for immediate takeoff. We were still completing takeoff checklist while on runway. I pushed confign button and got flaps warning. I chose to taxi clear and figure out if anything else was missed. We reset flaps and departed normally. Supplemental information from acn 567246: I started the after start flow, but was again distraction by radio xmissions from ground. At this point, I had completed part of the after start flow but had not set the flaps as I was supposed to. I was clearing as we started to taxi and just forgot to complete the checklist. It was a short taxi to the takeoff runway 27L. Small jet passed over the runway threshold. Tower told us to taxi onto the runway for an immediate takeoff, as another aircraft was on 4 mi final. The captain called for the before takeoff checklist. I made the takeoff announcement to the flight attendants, changed one of the radio frequencys to departure, and started the checklist. I was running the checklist as we took the active when we got a flap confign aural caution and EICAS message. The captain had pushed the takeoff check switch which had activated the flap confign warning EICAS message. It took a second or two to understand what we had. The captain retarded throttles and the aural warning ceased. At this point, we had rolled a short distance and just to verify what we had, elected to exit the runway and taxi back to the runway for another try. At the same time, tower told the aircraft on final to go around. We only realized our problem as we were taking the runway and in playing it safe, caused another aircraft to go around.

Related reports:

Google
 

Original NASA ASRS Text

Title: B757-300 CREW DID NOT HAVE THE TKOF FLAPS SET, AND HAD A TKOF WARNING HORN, REJECTED TKOF CAUSING PBI LCL CTLR TO ISSUE GAR TO ACFT ON FINAL.

Narrative: DID NOT SET FLAPS ON AFTER START CHKLIST. WAS RUSHED FOR TKOF BY OTHER ACFT ON FINAL. CLRED FOR IMMEDIATE TKOF. WE WERE STILL COMPLETING TKOF CHKLIST WHILE ON RWY. I PUSHED CONFIGN BUTTON AND GOT FLAPS WARNING. I CHOSE TO TAXI CLR AND FIGURE OUT IF ANYTHING ELSE WAS MISSED. WE RESET FLAPS AND DEPARTED NORMALLY. SUPPLEMENTAL INFO FROM ACN 567246: I STARTED THE AFTER START FLOW, BUT WAS AGAIN DISTR BY RADIO XMISSIONS FROM GND. AT THIS POINT, I HAD COMPLETED PART OF THE AFTER START FLOW BUT HAD NOT SET THE FLAPS AS I WAS SUPPOSED TO. I WAS CLRING AS WE STARTED TO TAXI AND JUST FORGOT TO COMPLETE THE CHKLIST. IT WAS A SHORT TAXI TO THE TKOF RWY 27L. SMALL JET PASSED OVER THE RWY THRESHOLD. TWR TOLD US TO TAXI ONTO THE RWY FOR AN IMMEDIATE TKOF, AS ANOTHER ACFT WAS ON 4 MI FINAL. THE CAPT CALLED FOR THE BEFORE TKOF CHKLIST. I MADE THE TKOF ANNOUNCEMENT TO THE FLT ATTENDANTS, CHANGED ONE OF THE RADIO FREQS TO DEP, AND STARTED THE CHKLIST. I WAS RUNNING THE CHKLIST AS WE TOOK THE ACTIVE WHEN WE GOT A FLAP CONFIGN AURAL CAUTION AND EICAS MESSAGE. THE CAPT HAD PUSHED THE TKOF CHK SWITCH WHICH HAD ACTIVATED THE FLAP CONFIGN WARNING EICAS MESSAGE. IT TOOK A SECOND OR TWO TO UNDERSTAND WHAT WE HAD. THE CAPT RETARDED THROTTLES AND THE AURAL WARNING CEASED. AT THIS POINT, WE HAD ROLLED A SHORT DISTANCE AND JUST TO VERIFY WHAT WE HAD, ELECTED TO EXIT THE RWY AND TAXI BACK TO THE RWY FOR ANOTHER TRY. AT THE SAME TIME, TWR TOLD THE ACFT ON FINAL TO GO AROUND. WE ONLY REALIZED OUR PROB AS WE WERE TAKING THE RWY AND IN PLAYING IT SAFE, CAUSED ANOTHER ACFT TO GO AROUND.

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.