SEA02LA169

The pilot reported that after the aircraft touched on runway 19, he needed to apply left rudder input, followed by left braking action to counteract the weathervane effect. The pilot stated that despite the increased inputs, the airplane departed the runway centerline and traveled off the side of the runway. The left main landing gear separated at the gear leg attachment and the left wing contacted the surface. Shortly after the accident, the winds were reported from 300 degrees at 8 knots. Post accident inspection of the gear leg, gear leg attach bolt, gear box and brake indicated a side load. No anomalies were reported for the brake system.

On August 31, 2002, about 1130 mountain daylight time, a tail wheel equipped Cessna 172, N6830A, registered to I Fly Strand Aviation and operated by a private pilot as a 14 CFR Part 91 personal flight, was substantially damaged during the landing roll at Yellowstone Airport, West Yellowstone, Montana. Visual meteorological conditions prevailed at the time and no flight plan was filed. The private pilot and his passenger were not injured. The flight departed from Bozeman, Montana, about 45 minutes prior to the accident.

During a telephone interview and subsequent written statement, the pilot reported that the fixed base operator on the airport was reporting the winds as favoring runway 01, with winds out of the west at 10 knots. The pilot reported that aircraft were also landing on runway 19, so he flew over the runway to determine the wind direction. The wind sock on the approach end of 19 looked okay, however, the wind sock at mid-field indicated a wind from the west. The pilot chose to set-up for a landing on runway 19. The pilot stated that after the airplane touched down, he needed to apply left rudder input, followed by left braking action to "counteract the somewhat weak weathervane effect." The pilot reported that despite the increased inputs, the airplane departed the runway centerline and traveled off the side of the runway. The left main landing gear separated at the gear leg attachment and the left wing contacted the surface. The airplane pivoted and came to rest almost 90 degrees to the runway heading.

At 1146, Yellowstone Airport weather facility was reporting winds from 300 degrees at 8 knots.

The airplane was moved to Beegles Aircraft Service, Greeley, Colorado. An Air Safety Investigator with the National Transportation Safety Board and an Air Safety Investigator from Cessna Aircraft Company inspected the left main gear leg, left gear leg attach bolt, the left gear leg box and left gear brake. The investigators reported that it appeared that the left main gear experienced a side load and that the left gear leg attach bolt was bent. No anomalies were reported for the brake system. The outer tire rim rubber was scuffed and the outer wheel hub was damaged.