Narrative:

De-iced aircraft; assigned runway 27; on taxi out. Changed runway to runway 36L. After running taxi checklist; runway changed to runway 27. Stopped aircraft short of runway 27 to start second engine and run before takeoff checks and to run up engine per anti-ice procedure. Runup of left engine (30 seconds at 70% N1) completed. Tower cleared us into position and hold runway 27. We were the first on runway 27 since it had been swept anc chemically treated. Right engine runup commenced while taking runway; before takeoff check complete. Tower cleared us for takeoff with traffic on 3 mi final for intersecting runway 36L. As I turned the aircraft onto centerline; I pulled back right thrust lever; brought left thrust lever physically even with right thrust lever. Tracking straight; I gave airplane to the copilot (it was his leg). I saw that left engine N1 was 40%; usually when we engage autothrottles. He engaged autothrottles; and right engine spooled up ahead of the left. Aircraft jumped to the left; we both pulled thrust levers to idle; full braking and steering right; but aircraft's nosewheel went off the pavement approximately 1 ft. Tower; passenger; company; crew advised. Ran after landing and engine shutdown checklists. No injuries; 2 tires cut. Passenger left on stair truck through aft right door. Static takeoff would have prevented this; rushed clearance also contributed.

Google
 

Original NASA ASRS Text

Title: LGT EXPERIENCES RWY EXCURSION AFTER STARTING TKOF ROLL IN SNOW ON RECENTLY PLOWED AND TREATED RWY.

Narrative: DE-ICED ACFT; ASSIGNED RWY 27; ON TAXI OUT. CHANGED RWY TO RWY 36L. AFTER RUNNING TAXI CHKLIST; RWY CHANGED TO RWY 27. STOPPED ACFT SHORT OF RWY 27 TO START SECOND ENG AND RUN BEFORE TKOF CHKS AND TO RUN UP ENG PER ANTI-ICE PROC. RUNUP OF L ENG (30 SECONDS AT 70% N1) COMPLETED. TWR CLRED US INTO POS AND HOLD RWY 27. WE WERE THE FIRST ON RWY 27 SINCE IT HAD BEEN SWEPT ANC CHEMICALLY TREATED. R ENG RUNUP COMMENCED WHILE TAKING RWY; BEFORE TKOF CHK COMPLETE. TWR CLRED US FOR TKOF WITH TFC ON 3 MI FINAL FOR INTERSECTING RWY 36L. AS I TURNED THE ACFT ONTO CTRLINE; I PULLED BACK R THRUST LEVER; BROUGHT L THRUST LEVER PHYSICALLY EVEN WITH R THRUST LEVER. TRACKING STRAIGHT; I GAVE AIRPLANE TO THE COPLT (IT WAS HIS LEG). I SAW THAT L ENG N1 WAS 40%; USUALLY WHEN WE ENGAGE AUTOTHROTTLES. HE ENGAGED AUTOTHROTTLES; AND R ENG SPOOLED UP AHEAD OF THE L. ACFT JUMPED TO THE L; WE BOTH PULLED THRUST LEVERS TO IDLE; FULL BRAKING AND STEERING R; BUT ACFT'S NOSEWHEEL WENT OFF THE PAVEMENT APPROX 1 FT. TWR; PAX; COMPANY; CREW ADVISED. RAN AFTER LNDG AND ENG SHUTDOWN CHKLISTS. NO INJURIES; 2 TIRES CUT. PAX LEFT ON STAIR TRUCK THROUGH AFT R DOOR. STATIC TKOF WOULD HAVE PREVENTED THIS; RUSHED CLRNC ALSO CONTRIBUTED.

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.