Narrative:

After receiving takeoff clearance, throttles were brought to takeoff and power and brakes were released. At approximately 40 KTS 'takeoff warning' horn sounded. Takeoff was aborted and we cleared runway. Tower was notified we did not require assistance. We suspected flap position, which was set to 13 degree to be problem. We recycled flaps, checked warning systems and made an uneventful takeoff. Whenever flaps are set to any setting near 13 degree, this 'takeoff warning' nuisance usually occurs. Between 13-15 is where stall warning computer selects flaps to full extend. I believe flap settings should be restr from the 12-15 degree range instead of 13-15 degree range. This would stop the problem. Callback conversation with reporter revealed the following: company ACARS gives us a computed maximum performance flap setting for takeoff. We have several options other than selecting the 13 degree setting and more and more pilots are choosing not to use 13 degree because somehow the setting does not allow enough margin for equipment adjustment, etc and frequently results in a takeoff warning horn. Company is aware of the problem and is working with manufacturer, contemplating changing flap setting procedure. We normally advance one throttle into the takeoff range during taxi to test the horn, which we did in this instance but apparently vibration on the rough runway, flexing of the aircraft, etc triggered the takeoff horn. FAA is apparently interested in any abort and is suggesting a maintenance sign off before flight crew attempts another takeoff.

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Original NASA ASRS Text

Title: FLT CREW OF MLG ABORTED TKOF AT LGA ACCOUNT FLAP WARNING. RECYCLED CONTROLS TO SAME SETTING, TKOF WAS THEN NORMAL.

Narrative: AFTER RECEIVING TKOF CLRNC, THROTTLES WERE BROUGHT TO TKOF AND POWER AND BRAKES WERE RELEASED. AT APPROX 40 KTS 'TKOF WARNING' HORN SOUNDED. TKOF WAS ABORTED AND WE CLRED RWY. TWR WAS NOTIFIED WE DID NOT REQUIRE ASSISTANCE. WE SUSPECTED FLAP POSITION, WHICH WAS SET TO 13 DEG TO BE PROBLEM. WE RECYCLED FLAPS, CHECKED WARNING SYSTEMS AND MADE AN UNEVENTFUL TKOF. WHENEVER FLAPS ARE SET TO ANY SETTING NEAR 13 DEG, THIS 'TKOF WARNING' NUISANCE USUALLY OCCURS. BETWEEN 13-15 IS WHERE STALL WARNING COMPUTER SELECTS FLAPS TO FULL EXTEND. I BELIEVE FLAP SETTINGS SHOULD BE RESTR FROM THE 12-15 DEG RANGE INSTEAD OF 13-15 DEG RANGE. THIS WOULD STOP THE PROBLEM. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: COMPANY ACARS GIVES US A COMPUTED MAX PERFORMANCE FLAP SETTING FOR TKOF. WE HAVE SEVERAL OPTIONS OTHER THAN SELECTING THE 13 DEG SETTING AND MORE AND MORE PLTS ARE CHOOSING NOT TO USE 13 DEG BECAUSE SOMEHOW THE SETTING DOES NOT ALLOW ENOUGH MARGIN FOR EQUIPMENT ADJUSTMENT, ETC AND FREQUENTLY RESULTS IN A TKOF WARNING HORN. COMPANY IS AWARE OF THE PROBLEM AND IS WORKING WITH MANUFACTURER, CONTEMPLATING CHANGING FLAP SETTING PROC. WE NORMALLY ADVANCE ONE THROTTLE INTO THE TKOF RANGE DURING TAXI TO TEST THE HORN, WHICH WE DID IN THIS INSTANCE BUT APPARENTLY VIBRATION ON THE ROUGH RWY, FLEXING OF THE ACFT, ETC TRIGGERED THE TKOF HORN. FAA IS APPARENTLY INTERESTED IN ANY ABORT AND IS SUGGESTING A MAINT SIGN OFF BEFORE FLT CREW ATTEMPTS ANOTHER TKOF.

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