ANC05LA142

The airline transport certificated pilot was conducting a personal cross-country flight. He said during landing at a sod covered, off airport site, the left main landing gear collapsed. Upon inspection, he discovered that the left main landing gear strut attachment bolt had broken. He reported that a witness told him he initially bounced 12-18 inches on landing before settling onto the landing area a second time. The pilot said there were no known mechanical anomalies with the airplane prior to the accident. The airplane sustained structural damage to the gear box, left wing, aileron, and horizontal stabilizer. An examination of the landing gear attachment bolt, and new, exemplar bolts, by a metallurgist at the NTSB materials laboratory in Washington, D.C., revealed that the bolt had broken in a "ductile overstress separation in bending and shear mode." The laboratory report notes that the bolt was made of the appropriate material, and was of the proper dimensions.

On September 9, 2005, about 1930 Alaska daylight time, a Cessna 185E airplane, N1592F, sustained substantial damage when the left main landing gear collapsed during an off airport landing, about 30 miles southeast of Pilot Point, Alaska. The airplane was being operated by the pilot as a visual flight rules (VFR) personal cross-country flight under Title 14, CFR Part 91, when the accident occurred. The solo private pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated at the Pilot Point Airport, Pilot Point, about 1900.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on September 10, the pilot said during landing at a sod covered, off airport site, the left main landing gear collapsed. The airplane sustained structural damage to the gear box, left wing, aileron, and horizontal stabilizer. The pilot said that upon examination of the main landing gear strut, he found the main landing gear attachment bolt had broken. He said there were no known mechanical anomalies with the airplane prior to the accident.

In a written statement to the NTSB dated October 10, the pilot wrote that a by-stander told him that upon initial contact during landing, the airplane bounced 12-18 inches off the ground before settling onto the runway area a second time.

The broken bolt, along with new, exemplar bolts, from the same production lot, were sent to the NTSB materials laboratory in Washington, D.C., for examination. The examination revealed that the landing gear retention bolt had broken in a "ductile overstress separation in bending and shear mode." The examining metallurgist concluded the bolt was made of the appropriate material, and was of the proper dimensions.