Narrative:

During taxi, the captain called for the before takeoff checklist. I had just started my 'before takeoff' flow pattern when the flight attendant came up to report a passenger problem. I felt I had completed the before takeoff flow correctly. I then started to read the checklist to verify the items when the tower interrupted, 'cleared for takeoff without delay, traffic short final.' I responded, 'roger, cleared for takeoff.' we had to solve a passenger problem, and prepare for takeoff. I then completed reading and verifying the remainder of the checklist items. It was nighttime and very dark in the cockpit. We apparently missed the fact that the condition levers were not all the way forward during the checklist. I know that distraction, darkness, parallax, and fatigue all led to our not noticing the exact position of the condition levers. As we started the takeoff run, a takeoff warning horn sounded. The captain aborted the takeoff and pulled off the runway. We performed the checklist items again. We discovered the discrepancy (concerning the condition lever position), elected to return for takeoff, and departed without incident. I do know that it is recommended to restart a flow pattern or restart a checklist after an interruption or distraction. I know now that I will do it every time without exception, physically touch the condition levers during the checklist, and decline a takeoff clearance until all problems are resolved.

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Original NASA ASRS Text

Title: CAPT OF AN MDT ABORTED TKOF DUE TO A TKOF WARNING HORN INDICATING THAT THE ACFT WAS NOT CONFIGURED FOR TKOF.

Narrative: DURING TAXI, THE CAPT CALLED FOR THE BEFORE TKOF CHKLIST. I HAD JUST STARTED MY 'BEFORE TKOF' FLOW PATTERN WHEN THE FLT ATTENDANT CAME UP TO RPT A PAX PROB. I FELT I HAD COMPLETED THE BEFORE TKOF FLOW CORRECTLY. I THEN STARTED TO READ THE CHKLIST TO VERIFY THE ITEMS WHEN THE TWR INTERRUPTED, 'CLRED FOR TKOF WITHOUT DELAY, TFC SHORT FINAL.' I RESPONDED, 'ROGER, CLRED FOR TKOF.' WE HAD TO SOLVE A PAX PROB, AND PREPARE FOR TKOF. I THEN COMPLETED READING AND VERIFYING THE REMAINDER OF THE CHKLIST ITEMS. IT WAS NIGHTTIME AND VERY DARK IN THE COCKPIT. WE APPARENTLY MISSED THE FACT THAT THE CONDITION LEVERS WERE NOT ALL THE WAY FORWARD DURING THE CHKLIST. I KNOW THAT DISTR, DARKNESS, PARALLAX, AND FATIGUE ALL LED TO OUR NOT NOTICING THE EXACT POS OF THE CONDITION LEVERS. AS WE STARTED THE TKOF RUN, A TKOF WARNING HORN SOUNDED. THE CAPT ABORTED THE TKOF AND PULLED OFF THE RWY. WE PERFORMED THE CHKLIST ITEMS AGAIN. WE DISCOVERED THE DISCREPANCY (CONCERNING THE CONDITION LEVER POS), ELECTED TO RETURN FOR TKOF, AND DEPARTED WITHOUT INCIDENT. I DO KNOW THAT IT IS RECOMMENDED TO RESTART A FLOW PATTERN OR RESTART A CHKLIST AFTER AN INTERRUPTION OR DISTR. I KNOW NOW THAT I WILL DO IT EVERY TIME WITHOUT EXCEPTION, PHYSICALLY TOUCH THE CONDITION LEVERS DURING THE CHKLIST, AND DECLINE A TKOF CLRNC UNTIL ALL PROBS ARE RESOLVED.

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.