Narrative:

Flight den to cys was holding on the horse LOM for visibility conditions to improve for runway 26. Cys approach reported visibility for runway 26 had improved to 1/2 mi. The captain turned inbound and was established on the localizer outside the LOM. Inside the LOM, tower reported winds of 330 degrees at 15 KTS. The approach was stabilized to T/D. I called out lead in lights at 50' above minimums and approach lights, runway edge lights at minimums. The aircraft touched down on centerline 1500' down the runway. Once down the aircraft began to weathervane into the wind. Sliding to the left edge of the runway where it struck and damaged a runway edge light. Positive control was quickly established by utilizing differential engine power which directed the aircraft back to runway centerline. After the captain and I had determined the aircraft had not sustained any significant damage, the aircraft was taxied to the ramp. The captain notified cys tower of the excursion and requested a runway inspection to be conducted by he, myself and an aircraft employee. The runway inspection results are as follows: runway was found to be contaminated with 1 1/2' of slush (a field condition report filed 27 mins prior to T/D reported a thin layer of slush on the runway, braking action good). The aircraft touched down on centerline 1500' down the runway. The captain had used aileron (light wing down) to counter the right crosswind, since the right main gear had touched down and left impressions in the slush well before the left main gear touched down. My estimation of why the incident occurred are as follows: the wind conditions were significantly worse that advertised by the sequential report and tower. I estimate the winds at T/D and rollout to be from 330-350 degrees at 25-30 KTS. This belief was further confirmed by a conversation I had with a pilot who landed in cys 2 hours after us. He stated cys tower reported winds of 350 degrees at 15 KTS on short final. Upon T/D the pilot stated he nearly slid off the runway because of hydroplaning and windy conditions. He estimated he had encountered a direct crosswind of 25 KTS. Braking action on runway 26 was poor as it was contaminated with 1 1/2' of wet snow and slush (see field condition report above). The contaminated runway caused the aircraft to hydroplane and skid off the runway as it weathervaned into the wind. The captain did an extraordinary job of correcting the excursion by utilizing all means available to him, and by reacting quickly and correctly. To prohibit this from happening again, during adverse WX conditions, airport authorities should update field condition reports in a more timely fashion. Additionally, major consideration should be given to the location of wind reporting stations. Certain winds may be recorded in error due to mechanical disturbance or because of the sheltered location of the station. Callback conversation with reporter revealed the following: reporter states braking action tests were done with a pick up truck on the runway, then reported to pilots. An large transport arrived 1/2 hour after reporter, touched down and did a go around and diverted to an alternate. Supplemental information from acn 106909: upon landing in den the aircraft veered left when I entered ground fine (beta range). This indicates a slight misrigging of the engine that normally would not affect a landing. However, in this case such a yawing moment coupled with a higher than reported crosswind and a runway condition much worse than reported would be enough to cause the aircraft veer to the left.

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Original NASA ASRS Text

Title: LOSS OF ACFT CONTROL DUE TO SLUSH ON RWY AND HIGHER THAN REPORTED CROSSWIND.

Narrative: FLT DEN TO CYS WAS HOLDING ON THE HORSE LOM FOR VISIBILITY CONDITIONS TO IMPROVE FOR RWY 26. CYS APCH RPTED VISIBILITY FOR RWY 26 HAD IMPROVED TO 1/2 MI. THE CAPT TURNED INBND AND WAS ESTABLISHED ON THE LOC OUTSIDE THE LOM. INSIDE THE LOM, TWR RPTED WINDS OF 330 DEGS AT 15 KTS. THE APCH WAS STABILIZED TO T/D. I CALLED OUT LEAD IN LIGHTS AT 50' ABOVE MINIMUMS AND APCH LIGHTS, RWY EDGE LIGHTS AT MINIMUMS. THE ACFT TOUCHED DOWN ON CENTERLINE 1500' DOWN THE RWY. ONCE DOWN THE ACFT BEGAN TO WEATHERVANE INTO THE WIND. SLIDING TO THE LEFT EDGE OF THE RWY WHERE IT STRUCK AND DAMAGED A RWY EDGE LIGHT. POSITIVE CTL WAS QUICKLY ESTABLISHED BY UTILIZING DIFFERENTIAL ENG PWR WHICH DIRECTED THE ACFT BACK TO RWY CENTERLINE. AFTER THE CAPT AND I HAD DETERMINED THE ACFT HAD NOT SUSTAINED ANY SIGNIFICANT DAMAGE, THE ACFT WAS TAXIED TO THE RAMP. THE CAPT NOTIFIED CYS TWR OF THE EXCURSION AND REQUESTED A RWY INSPECTION TO BE CONDUCTED BY HE, MYSELF AND AN ACFT EMPLOYEE. THE RWY INSPECTION RESULTS ARE AS FOLLOWS: RWY WAS FOUND TO BE CONTAMINATED WITH 1 1/2' OF SLUSH (A FIELD CONDITION RPT FILED 27 MINS PRIOR TO T/D RPTED A THIN LAYER OF SLUSH ON THE RWY, BRAKING ACTION GOOD). THE ACFT TOUCHED DOWN ON CENTERLINE 1500' DOWN THE RWY. THE CAPT HAD USED AILERON (LIGHT WING DOWN) TO COUNTER THE RIGHT XWIND, SINCE THE RIGHT MAIN GEAR HAD TOUCHED DOWN AND LEFT IMPRESSIONS IN THE SLUSH WELL BEFORE THE LEFT MAIN GEAR TOUCHED DOWN. MY ESTIMATION OF WHY THE INCIDENT OCCURRED ARE AS FOLLOWS: THE WIND CONDITIONS WERE SIGNIFICANTLY WORSE THAT ADVERTISED BY THE SEQUENTIAL RPT AND TWR. I ESTIMATE THE WINDS AT T/D AND ROLLOUT TO BE FROM 330-350 DEGS AT 25-30 KTS. THIS BELIEF WAS FURTHER CONFIRMED BY A CONVERSATION I HAD WITH A PLT WHO LANDED IN CYS 2 HRS AFTER US. HE STATED CYS TWR RPTED WINDS OF 350 DEGS AT 15 KTS ON SHORT FINAL. UPON T/D THE PLT STATED HE NEARLY SLID OFF THE RWY BECAUSE OF HYDROPLANING AND WINDY CONDITIONS. HE ESTIMATED HE HAD ENCOUNTERED A DIRECT XWIND OF 25 KTS. BRAKING ACTION ON RWY 26 WAS POOR AS IT WAS CONTAMINATED WITH 1 1/2' OF WET SNOW AND SLUSH (SEE FIELD CONDITION RPT ABOVE). THE CONTAMINATED RWY CAUSED THE ACFT TO HYDROPLANE AND SKID OFF THE RWY AS IT WEATHERVANED INTO THE WIND. THE CAPT DID AN EXTRAORDINARY JOB OF CORRECTING THE EXCURSION BY UTILIZING ALL MEANS AVAILABLE TO HIM, AND BY REACTING QUICKLY AND CORRECTLY. TO PROHIBIT THIS FROM HAPPENING AGAIN, DURING ADVERSE WX CONDITIONS, ARPT AUTHORITIES SHOULD UPDATE FIELD CONDITION RPTS IN A MORE TIMELY FASHION. ADDITIONALLY, MAJOR CONSIDERATION SHOULD BE GIVEN TO THE LOCATION OF WIND RPTING STATIONS. CERTAIN WINDS MAY BE RECORDED IN ERROR DUE TO MECHANICAL DISTURBANCE OR BECAUSE OF THE SHELTERED LOCATION OF THE STATION. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR STATES BRAKING ACTION TESTS WERE DONE WITH A PICK UP TRUCK ON THE RWY, THEN RPTED TO PLTS. AN LGT ARRIVED 1/2 HR AFTER RPTR, TOUCHED DOWN AND DID A GAR AND DIVERTED TO AN ALTERNATE. SUPPLEMENTAL INFO FROM ACN 106909: UPON LNDG IN DEN THE ACFT VEERED LEFT WHEN I ENTERED GND FINE (BETA RANGE). THIS INDICATES A SLIGHT MISRIGGING OF THE ENG THAT NORMALLY WOULD NOT AFFECT A LNDG. HOWEVER, IN THIS CASE SUCH A YAWING MOMENT COUPLED WITH A HIGHER THAN RPTED XWIND AND A RWY CONDITION MUCH WORSE THAN RPTED WOULD BE ENOUGH TO CAUSE THE ACFT VEER TO THE LEFT.

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.