Narrative:

WX at landing: approximately 20 overcast 1/2 sf R22 RVR 55 td 45 ro. Wind estimated 300 13620. Runway 22 braking action reported poor by medium large transport. Approach and landing uneventful. Aircraft brought to stop with 2500 ft remaining. Medium autobrakes and reverse EPR 1.5 were used. At about 40 KTS first officer disengaged autobrakes and manually brought aircraft to a stop. Braking action was indeed poor. Runway surface approximately 60 ft either side of centerline was 1-2 inches of snow over patchy ice. Captain took aircraft to make 180 degree turn on runway as directed by tower. He taxied slowly to right edge of runway, though it was difficult to judge just where that was. There was 1-2 ft of snow drifts (unplowed) covering the 10-20 ft closest to runway edge lights. Captain began left 180 degree turn at min power and traveling very slowly. Turn was normal through 90 degrees of turn. Aircraft was moving so slowly captain felt he needed power to prevent aircraft from simply coming to a stop. He added small amount of power on right engine. By the time this throttle movement resulted in increased thrust aircraft had completed about 120 degrees of turn. The effect of the additional thrust was to propel the aircraft along the longitudinal axis rather than assist in the left turn. This was because by now the nose wheel had encountered 1-2 ft of snow drift along the opposite side of the runway. Traction under this snow was even worse than on the runway centerline, and the nose wheel tires could not hold the turn with the additional thrust. The nose wheels departed the runway edge after 120 degrees of turn, coming to rest 10-15 ft from the runway edge. I believe if the runway surface underneath the deeper snow at runway edge had been as good as the center part of the runway, the turn would have been completed without incident. We had no way of knowing how slippery the surface was at the runway edge. Runway downsloping crown and crosswind could have been contributory factors. There were no passenger injuries and the aircraft was not damaged. Lessons: extreme care should be used when adding power on very slick surfaces. Might be better to shut down and be towed to the gate. Also, it might be prudent as a precaution to make the 180 degree turn abeam an exit taxiway in case traction is lost in the turn. If it is, aircraft may stop on hard surface where it can be towed back on runway and to gate.

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Original NASA ASRS Text

Title: RWY EXCURSION.

Narrative: WX AT LNDG: APPROX 20 OVCST 1/2 SF R22 RVR 55 TD 45 RO. WIND ESTIMATED 300 13620. RWY 22 BRAKING ACTION RPTED POOR BY MLG. APCH AND LNDG UNEVENTFUL. ACFT BROUGHT TO STOP WITH 2500 FT REMAINING. MEDIUM AUTOBRAKES AND REVERSE EPR 1.5 WERE USED. AT ABOUT 40 KTS FO DISENGAGED AUTOBRAKES AND MANUALLY BROUGHT ACFT TO A STOP. BRAKING ACTION WAS INDEED POOR. RWY SURFACE APPROX 60 FT EITHER SIDE OF CTRLINE WAS 1-2 INCHES OF SNOW OVER PATCHY ICE. CAPT TOOK ACFT TO MAKE 180 DEG TURN ON RWY AS DIRECTED BY TWR. HE TAXIED SLOWLY TO R EDGE OF RWY, THOUGH IT WAS DIFFICULT TO JUDGE JUST WHERE THAT WAS. THERE WAS 1-2 FT OF SNOW DRIFTS (UNPLOWED) COVERING THE 10-20 FT CLOSEST TO RWY EDGE LIGHTS. CAPT BEGAN L 180 DEG TURN AT MIN PWR AND TRAVELING VERY SLOWLY. TURN WAS NORMAL THROUGH 90 DEGS OF TURN. ACFT WAS MOVING SO SLOWLY CAPT FELT HE NEEDED PWR TO PREVENT ACFT FROM SIMPLY COMING TO A STOP. HE ADDED SMALL AMOUNT OF PWR ON R ENG. BY THE TIME THIS THROTTLE MOVEMENT RESULTED IN INCREASED THRUST ACFT HAD COMPLETED ABOUT 120 DEGS OF TURN. THE EFFECT OF THE ADDITIONAL THRUST WAS TO PROPEL THE ACFT ALONG THE LONGITUDINAL AXIS RATHER THAN ASSIST IN THE L TURN. THIS WAS BECAUSE BY NOW THE NOSE WHEEL HAD ENCOUNTERED 1-2 FT OF SNOW DRIFT ALONG THE OPPOSITE SIDE OF THE RWY. TRACTION UNDER THIS SNOW WAS EVEN WORSE THAN ON THE RWY CTRLINE, AND THE NOSE WHEEL TIRES COULD NOT HOLD THE TURN WITH THE ADDITIONAL THRUST. THE NOSE WHEELS DEPARTED THE RWY EDGE AFTER 120 DEGS OF TURN, COMING TO REST 10-15 FT FROM THE RWY EDGE. I BELIEVE IF THE RWY SURFACE UNDERNEATH THE DEEPER SNOW AT RWY EDGE HAD BEEN AS GOOD AS THE CTR PART OF THE RWY, THE TURN WOULD HAVE BEEN COMPLETED WITHOUT INCIDENT. WE HAD NO WAY OF KNOWING HOW SLIPPERY THE SURFACE WAS AT THE RWY EDGE. RWY DOWNSLOPING CROWN AND XWIND COULD HAVE BEEN CONTRIBUTORY FACTORS. THERE WERE NO PAX INJURIES AND THE ACFT WAS NOT DAMAGED. LESSONS: EXTREME CARE SHOULD BE USED WHEN ADDING PWR ON VERY SLICK SURFACES. MIGHT BE BETTER TO SHUT DOWN AND BE TOWED TO THE GATE. ALSO, IT MIGHT BE PRUDENT AS A PRECAUTION TO MAKE THE 180 DEG TURN ABEAM AN EXIT TAXIWAY IN CASE TRACTION IS LOST IN THE TURN. IF IT IS, ACFT MAY STOP ON HARD SURFACE WHERE IT CAN BE TOWED BACK ON RWY AND TO GATE.

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.