NTSB Identification: CHI99LA092.
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Accident occurred Monday, February 15, 1999 in LAWRENCEVILLE, IL
Probable Cause Approval Date: 06/22/2000
Aircraft: Cessna 172RG, registration: N9506D
Injuries: 2 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
During climb-out both pilots heard a pop from the right side of the aircraft under the right seat. The CFI performed a landing gear extension. The left landing gear would extend and lock, but the right main gear would extend partially and then retract simultaneously as the left main landing gear would lower and lock. The manual landing gear extension procedures were tried, but the right main landing gear failed to extend. An emergency landing was attempted. The airplane veered off the right side of the runway during the landing rollout. The right wing and right horizontal stabilizer were damaged when they impacted the ground. The examination of the right main landing gear actuator assembly revealed the actuator body was cracked in two locations near the cups for the bearings. One of the cracks had fatigue striations that originated at the corner formed by the intersection of the 2.25 inch inner-diameter surface of the gear housing and the 1.0 inch inner-diameter surface of the linear actuator portion of the actuator housing. The examination of the corner revealed the presence of circumferential scouring marks consistent with grinding or filing marks. The maintenance logbooks indicated that the landing gear actuator was originally equipped on the airplane and had a total of approximately 7,000 flight hours and 21,000 cycles. There is no life or component time limit listed for the component by the airplane manufacturer.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: the fatigue fracture of the landing gear actuator. Full narrative available
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