CORP SMT BELOW NORMAL APCH PATH BECAUSE OF WIND SHEAR STRUCK SNOW BANK AT END OF RWY.

Narrative

FLT DEPARTED BRIDGEPORT; CT AT XA38 LOCAL TIME; WITH FOUR ON BOARD; AND ARRIVED AT ELYRIA; OH AT XF18 LOCAL TIME; AFTER A ONE AND ONE QUARTER HOUR STOP IN DU BOISE; PA. BOTH LEGS WERE ON IFR FLT PLANS; HOWEVER WITHIN 10 MILES OF ELYRIA; WEATHER HAD IMPROVED TO ABOUT 5000 SCATTERED; WITH FIVE PLUS MILES VISIBILITY; AND A STRONG NORTH WEST WIND. THE IFR FLT PLAN WAS CANCELLED A FEW MILES SE OF ELYRIA; AND AN ANNOUNCEMENT OF INTENTIONS MADE ON THE UNICOM FREQ. NO REPLY WAS RECEIVED. AN APCH WAS MADE TO RWY 27 AT ELYRIA. ON DESCENDING BELOW THE TREETOPS; A SUBSTANTIAL WINDSHEAR WAS ENCOUNTERED. THE ACFT SETTLED; AND STRUCK A SMALL SNOW BANK; WHERE THE OVERRUN AREA JOINS THE PAVED RWY. THE SNOW BANK WAS ABOUT 30 INCHES HIGH; AND THE ACFT WHEELS LEFT IMPRESSIONS ABOUT 5 INCHES DEEP IN THE TOP OF THE SNOWBANK. THE IMPACT DAMAGED THE NOSE GEAR STRUT; AND THE LEFT LANDING GEAR STRUT; WITH CONSEQUENTIAL DAMAGE TO OTHER PARTS AS THE ACFT CAME TO A STOP. BOTH THE RWY AND THE OVERRUN AREA WERE CLEAR AND SMOOTH. THE SNOW BANK APPEARED TO BE SNOW LEFT BEHIND AFTER PLOWING THE PAVED PORTION OF THE RWY. UPON INSPECTION; HOWEVER; IT WAS DISCOVERED THAT THERE HAD EVIDENTLY BEEN A SUBSTANTIAL THAW; FOLLOWED BY A HARD FREEZE. UNPLOWED SNOW ON THE OVERRUN AREA HAD MELTED INTO THE TURF; HEAVING A SMOOTH CRUSTY SURFACE. THE PAVED RWY WAS CLEAR; HOWEVER THE SNOW BANK HAD BECOME AN ICE BANK. THIS PROBLEM WAS NOT COVERED BY NOTAM. ARPT DATA: THE ELYRIA ARPT IS SHELTERED ALONG ITS NORTH SIDE BY A LINE OF TREES 50' TO 70' TALL; SOME OF WHICH STAND QUITE CLOSE TO THE RWY. THE APCH TO RWY 27 IS OVER AN OVERRUN ARE A 1170' LONG; WHICH IS LEVEL AND SMOOTH. THE TRANSITION FROM THE GRASS OVERRUN TO THE PAVED RWY IS ALSO LEVEL AND SMOOTH. THESE POINTS ARE MORE EVIDENT ON THE COMMERCIAL CHART ARPT DIAGRAM; THAN ON THAT PUBLISHED BY NOS. ACFT DATA: THE ACFT IS AN SMT; WITH A STOL CONVERSION. IT IS NOT KNOWN IF THE CONVERSION MAKES THIS ACFT MORE SUSCEPTIBLE TO WINDSHEAR THAN THE STANDARD ACFT.