NTSB Identification: SEA08LA069.
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Accident occurred Monday, February 04, 2008 in Parowan, UT
Probable Cause Approval Date: 05/28/2008
Aircraft: Piper PA-32R-301T, registration: N73BL
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

During a landing on a runway covered by about two to three inches of freshly fallen snow, one of the airplane's main landing gear impacted a snow covered mound of previously plowed snow that had hardened. That impact threw the airplane sideways, whereupon it collided with more of the previously plowed and hardened snow, resulting in the collapse of all the landing gear struts. The investigation determined that the last time that the runway was plowed, the snow had not been cleared all the way to the edge of the runway's paved surface, and there was therefore piles of previously plowed snow on the outer portions of the runway surface. Some of that snow was located 10 to 12 feet inboard of the edge of the runway surface. When the new snow fell, it became very hard to distinguish between the area where the previously cleared surface was covered only by the newly fallen snow, and the area where the chunks of previously plowed snow had piled up, hardened, and then been covered by the new snow. The pilot departed the same airport two days before the accident, and had seen the condition of the partially plowed runway. When he returned for landing on the day of the accident, he assumed that the old snow had been cleared away prior to the new snow falling, and that the entire runway was then covered only with the two to three inches of freshly fallen snow. Because he made that assumption, the pilot did not take advantage of the opportunity to perform a low approach and inspect the entire runway surface prior to landing. Soon after the airplane touched down, the pilot realized that the previously plowed snow was still on the edges of the runway, and that he had not touched down on the centerline. The pilot saw the chunks of snow-covered old snow prior to the impact, but before he could take remedial action, one of the airplane's main gear collided with a chunk of hardened old snow, and the accident sequence was initiated.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The pilot's improper in-flight decision not to over fly/inspect the snow covered runway prior to landing, and his failure to align the airplane over the centerline of the runway. Contributing to the accident was the snow covered runway, the airport operator's failure to properly plow and clear the runway, and hidden obstructions (previously plowed snow) under the freshly fallen snow.

Full narrative available

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