Accident Details
On February 4, 2008, at approximately 1130 mountain standard time, a Piper PA-32R-301T, registration N73BL, collided with hardened chunks of previously plowed snow during the landing roll at Parowan Airport, Parowan, Utah. The airline transport pilot, the sole occupant, was not injured. The airplane, owned and operated by the pilot, sustained substantial damage. The 14 CFR Part 91 personal transportation flight had departed Las Vegas, Nevada, about 0900 Pacific standard time and was operating in visual meteorological conditions. The pilot had originally been on an Instrument Flight Rules (IFR) flight plan but canceled his IFR clearance once the airport was in sight. There was no report of an ELT activation.
Pilot's Account
The pilot reported having landed at Parowan Airport many times over several years. On the accident day, the runway was covered with two to three inches of new snow. Due to the snow coverage, he could not easily identify the runway centerline. After touchdown, one main landing gear impacted a snow-covered mound of previously plowed snow. The impact threw the airplane sideways, leading to collisions with more plowed snow. During this sequence, all three landing gear struts collapsed, and the underside of the airplane's belly sustained considerable structural damage.
Investigation Findings
Investigation revealed that the last runway plowing by the Parowan Public Works Department had cleared only a 50-foot-wide swath on the 75-foot-wide runway surface. The remaining snow was piled at the edges. When new snow fell, it became difficult to distinguish between areas covered only by fresh snow and areas where hardened piles of previously plowed snow were hidden beneath the new snow.
In a telephone conversation with the NTSB Investigator-in-Charge, the pilot stated that when he departed Parowan two days prior, there was no snow on the center portion (a 50-foot irregular swath), but old plowed snow was piled along both sides of the runway, extending 10 to 12 feet from the edge onto the surface. Fresh snow fell while he was away. As he lined up for final approach, everything appeared white and flat. He assumed the old snow had been cleared before the new snowfall and that the entire runway was covered with only two to three inches of fresh snow.
Because of this assumption, the pilot did not conduct a low approach to inspect the runway before landing. Shortly after touchdown, he realized the previously plowed snow was still present on the runway edges and that he had not landed on the centerline. He saw the snow-covered chunks before impact but could not take remedial action before a main gear struck a hardened chunk, initiating the accident sequence.