St. Clair County Airport
Aircraft Accident/Incident Report

Port Huron, Michigan 48060
Saturday, January 17, 2004 11:05 EST

The airplane contacted a snow berm following a loss of directional control on landing. The pilot stated that while en route she listened to the automated weather observing system (AWOS) at the destination airport. She stated she received the weather along with a notice to airmen (NOTAM) which reported the runway braking [Bowmonk scale] measurements of 33, 35, and 36 MU along with light snow. The pilot stated she was handed off to air traffic control who relayed the same information. She stated that neither the AWOS nor the controller indicated any rapid conditions changes. The pilot stated she flew the ILS approach for runway 04 breaking out of the clouds at 600 feet above ground level. She stated "I don't believe there was ever any traction obtained, aircraft began a slide towards left side of runway." The pilot reported the left main gear contacted a snow berm on the side of the runway. The nose of the airplane swung around and contacted the berm, collapsing the nose gear. The airplane came to rest 20 feet off the left side of the runway approximately 1,000 feet past the approach end of the runway. The pilot reported that the owner of the local fixed base operator came out to the runway in his pickup truck to offer assistance. She stated he also experienced no braking and that his truck also slid into the snow berm on the side of the runway. The runway friction was tested at 1002 and the NOTAM was issued at 1015. The Bowmonk readings for runway 04 were 35, 33, and 36. The NOTAM issued contained the remarks 1/2 inch loose snow over patchy ice, compacted snow and ice all surfaces, executive ramp closed. Section 3 Airport Operations, Paragraph 4-3-9 of the Airmen's Information Manual states, "MU (friction) values range from 0 to 100 where zero is the lowest friction value and 100 is the maximum friction value obtainable. For frozen contaminants on runway surfaces, a MU value of 40 or less is the level when the aircraft braking performance starts to deteriorate and directional control begins to be less responsive. The lower the MU value, the less effective braking performance becomes and the more difficult directional control becomes." Winds at the airport were reported as being from 170 degrees at 8 knots.

The loss of directional control as a result of reduced braking performance due to a snow-covered runway. Also causal was the pilot's decision to land with a quartering tailwind. The snowbank was a contributing factor.