Narrative:

After completing the runway checks and taxiing onto the runway we were cleared for takeoff. At about 40 percent torque, we got a takeoff warning horn, so I, as the PF, aborted. We cleared the runway and checked the 6 items that cause the horn to sound. All items checked in the proper position, so we were cleared onto the runway again (position and hold). We rechked all 6 items again, in addition to the runway checks and everything was in the proper position. We were cleared for takeoff and at 40 percent torque we again got the takeoff warning horn. After clearing the runway again, I remembered a memo put out by the company in 1990 that addressed abnormalities with the takeoff warning horn. I consulted it and followed the procedure for selecting flaps to 15 degrees then back to the normal 5 degree position. The procedure worked and we did a normal takeoff (no horn) and the rest of the flight was uneventful. If this starts to be a recurring problem, I think it should be a procedure on the first flight of the day to select flaps to 15 degrees then back to 5 degrees. (Put into our originating checklist done prior to first flight of the day). The type of equipment I fly is the mdt.

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Original NASA ASRS Text

Title: ACR MDT PIC PERFORMS 2 TKOFS ABORTED ACCOUNT TKOF WARNING HORN RELATED TO ACFT CONFIGN.

Narrative: AFTER COMPLETING THE RWY CHKS AND TAXIING ONTO THE RWY WE WERE CLRED FOR TKOF. AT ABOUT 40 PERCENT TORQUE, WE GOT A TKOF WARNING HORN, SO I, AS THE PF, ABORTED. WE CLRED THE RWY AND CHKED THE 6 ITEMS THAT CAUSE THE HORN TO SOUND. ALL ITEMS CHKED IN THE PROPER POS, SO WE WERE CLRED ONTO THE RWY AGAIN (POS AND HOLD). WE RECHKED ALL 6 ITEMS AGAIN, IN ADDITION TO THE RWY CHKS AND EVERYTHING WAS IN THE PROPER POS. WE WERE CLRED FOR TKOF AND AT 40 PERCENT TORQUE WE AGAIN GOT THE TKOF WARNING HORN. AFTER CLRING THE RWY AGAIN, I REMEMBERED A MEMO PUT OUT BY THE COMPANY IN 1990 THAT ADDRESSED ABNORMALITIES WITH THE TKOF WARNING HORN. I CONSULTED IT AND FOLLOWED THE PROC FOR SELECTING FLAPS TO 15 DEGS THEN BACK TO THE NORMAL 5 DEG POS. THE PROC WORKED AND WE DID A NORMAL TKOF (NO HORN) AND THE REST OF THE FLT WAS UNEVENTFUL. IF THIS STARTS TO BE A RECURRING PROB, I THINK IT SHOULD BE A PROC ON THE FIRST FLT OF THE DAY TO SELECT FLAPS TO 15 DEGS THEN BACK TO 5 DEGS. (PUT INTO OUR ORIGINATING CHKLIST DONE PRIOR TO FIRST FLT OF THE DAY). THE TYPE OF EQUIP I FLY IS THE MDT.

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.