B737-700 flight crew has a confign warning during takeoff roll at las.

Attributes
ACN	719001
Time
Date	200611
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : las.airport
State Reference	NV
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	ground : takeoff roll ground : preflight
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 245
ASRS Report	719001
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : less severe non adherence : published procedure
Independent Detector	aircraft equipment other aircraft equipment : tkof warning horn other flight crewa other flight crewb
Resolutory Action	none taken : detected after the fact
Consequence	other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

We were taxiing for takeoff on runway 1R las. We were on taxiway D and I switched to the tower frequency. The tower controller cleared us for takeoff and told us to fly heading 315 degrees after departure. I was busy completing my flow and talking to ATC and I do not recall if the captain did the thrust lever check or not. We completed the before takeoff checklist. The aircraft was positioned onto the runway and the captain gave me control. I advanced the thrust levers and we received the takeoff warning horn. The captain immediately took control of the aircraft which had barely started rolling and rejected the takeoff. I notified ATC and we taxied clear of the runway. We completed our checklists and then went on to diagnose the problem. The aircraft was properly configured for takeoff (ie; trim; flaps; etc). The captain and I both checked the speed brake lever and it was in the down detent. The captain did numerous thrust lever checks to see if we could get the takeoff warning horn which we did each time. He checked the speed brake lever no less than 3 different times with his hand that it was in the down detent. We still received the takeoff warning horn. The captain decided to gate return. Upon returning to the gate; maintenance determined the problem to be dust build up in the switch area of the speed brake lever. They cleaned the area and the thrust lever check was normal. The logbook was signed off and we continued on. The captain needs to do the thrust lever check. I need to be positive that I have witnessed the completion of the thrust lever check.

Original NASA ASRS Text

Title: B737-700 FLT CREW HAS A CONFIGN WARNING DURING TKOF ROLL AT LAS.

Narrative: WE WERE TAXIING FOR TKOF ON RWY 1R LAS. WE WERE ON TXWY D AND I SWITCHED TO THE TWR FREQ. THE TWR CTLR CLRED US FOR TKOF AND TOLD US TO FLY HDG 315 DEGS AFTER DEP. I WAS BUSY COMPLETING MY FLOW AND TALKING TO ATC AND I DO NOT RECALL IF THE CAPT DID THE THRUST LEVER CHK OR NOT. WE COMPLETED THE BEFORE TKOF CHKLIST. THE ACFT WAS POSITIONED ONTO THE RWY AND THE CAPT GAVE ME CTL. I ADVANCED THE THRUST LEVERS AND WE RECEIVED THE TKOF WARNING HORN. THE CAPT IMMEDIATELY TOOK CTL OF THE ACFT WHICH HAD BARELY STARTED ROLLING AND REJECTED THE TKOF. I NOTIFIED ATC AND WE TAXIED CLR OF THE RWY. WE COMPLETED OUR CHKLISTS AND THEN WENT ON TO DIAGNOSE THE PROB. THE ACFT WAS PROPERLY CONFIGURED FOR TKOF (IE; TRIM; FLAPS; ETC). THE CAPT AND I BOTH CHKED THE SPD BRAKE LEVER AND IT WAS IN THE DOWN DETENT. THE CAPT DID NUMEROUS THRUST LEVER CHKS TO SEE IF WE COULD GET THE TKOF WARNING HORN WHICH WE DID EACH TIME. HE CHKED THE SPD BRAKE LEVER NO LESS THAN 3 DIFFERENT TIMES WITH HIS HAND THAT IT WAS IN THE DOWN DETENT. WE STILL RECEIVED THE TKOF WARNING HORN. THE CAPT DECIDED TO GATE RETURN. UPON RETURNING TO THE GATE; MAINT DETERMINED THE PROB TO BE DUST BUILD UP IN THE SWITCH AREA OF THE SPD BRAKE LEVER. THEY CLEANED THE AREA AND THE THRUST LEVER CHK WAS NORMAL. THE LOGBOOK WAS SIGNED OFF AND WE CONTINUED ON. THE CAPT NEEDS TO DO THE THRUST LEVER CHK. I NEED TO BE POSITIVE THAT I HAVE WITNESSED THE COMPLETION OF THE THRUST LEVER CHK.

Data retrieved from NASA's ASRS site as of January 2009 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.