CHI95LA147

The pilot stated the airplane bounced on the initial touchdown. When the airplane touched down a second time, the left main landing gear collapsed. After that, the weight of the aircraft shifted, and the nose wheel separated. The nose wheel strut then dug into the sod airstrip, and the airplane nosed over and came to rest inverted. An investigation revealed the left main gear attach bolt had failed. A metallurgical examination of the fracture revealed evidence of both fatigue and overstress separation.

On May 6, 1995, at 1530 eastern daylight time, a Cessna 172, N9347H, nosed over while landing on a private grass airstrip in Brooklyn, Michigan. The airplane was substantially damaged and the private pilot was not injured. The local 14 CFR Part 91 flight originated from Jackson, Michigan, at 1515 edt, and was not operating on a flight plan. Visual meteorological conditions prevailed.

The pilot stated he was landing to the northwest on the private airstrip when the accident occurred. He described the airstrip as being in "good to excellent" condition and that it had group of trees along the north side of the airstrip beginning approximately 450 feet past the approach end. The pilot stated he touched down at the beginning of this group of trees. He stated the airplane bounced, he added power, and the airplane touched down again approximately 250 feet further down the runway. Shortly after the second touchdown, the left main gear collapsed. According to the pilot, the weight of the airplane on the nose strut caused the nose wheel to break off. The nose gear strut then dug into the ground and the airplane nosed over.

The left main landing gear attach bolt was removed from the airplane and sent to the NTSB Materials Laboratory in Washington, D.C. The metallurgists report concluded the fractured surface showed areas of both fatigue and overstress separations. See attached metallurgists report for details.