What happened
During the climb phase of flight, the right main landing gear door actuator and the main landing gear door separated from the aircraft. The detached door actuator struck a residence, penetrating the roof and becoming lodged in the ceiling. Following the separation, the aircraft performed a return flight to Chicago. During this return leg, the airplane experienced a total loss of hydraulic pressure and fluid. Despite the hydraulic failure, the aircraft landed without incident and there were no injuries reported.
The investigation
Investigators examined the components involved in the separation. The examination found that both the operating gland housing and shaft, as well as the actuator rod end of the right main gear door, had fractured. A metallurgical examination of the fracture on the gland shaft revealed beach markings and other surface features. These findings were determined to be typical of unidirectional bending fatigue progression.