This February 2007 accident report is provided by the National Transportation Safety Board.
Aircraft: Cessna 172RG.
Location: Daytona Beach, Fla.
Aircraft damage: Substantial.
What reportedly happened: Shortly after takeoff, the pilot heard a loud bang, then noticed an unsafe landing gear indication.
He recycled the landing gear and noted that the right main gear would not fully deploy. The pilot couldn’t get the gear to come back up, either. He initiated a landing with the right main landing gear partially down. The airplane skidded to a stop on the runway.
The post-accident investigation revealed that the landing gear actuator body was cracked and separated at the forward bolt hole, preventing the main landing gear actuator piston from properly meshing with the sector gear, which precluded the landing gear from extending. The fracture surface was consistent with overload.
Probable cause: The fracture and failure of the right landing gear actuator, which resulted in a gear collapse during the landing roll.
For more information: ntsb.gov/ntsb/brief.asp?ev_id=20070214X00184&key=1.