Incident Overview
A pilot reported a landing gear anomaly during the initial climb phase after takeoff. Following the retraction of the landing gear, the hydraulic pump electric motor for the landing gear system continued to operate, despite the gear appearing fully retracted as observed through the landing gear mirror. The pilot then attempted a normal gear extension, but the landing gear did not indicate down and locked. Over the following hour, the pilot tried to manually extend the landing gear using the emergency manual gear extension hand pump. However, the mirror showed that the gear was only partially extended.
Emergency Landing and Damage
During the subsequent emergency landing, the main landing gear collapsed, and the airplane skidded to a stop on the runway. The right stabilator sustained substantial damage. No other damage or injuries were reported in the source.
Postaccident Examination
A postaccident examination of the landing gear system revealed that it was empty of hydraulic fluid. After the system was serviced with hydraulic fluid and operated, a leak was identified at the nose gear actuator, caused by a failure of a shaft seal. Tests demonstrated that the landing gear extension process could not be completed with the available fluid, and the manual landing gear pump did not have sufficient fluid remaining to extend all three landing gear.
Maintenance History
Review of the airplane's logbooks showed no records of service to the nose gear actuator or its shaft seal. Both components were the original manufactured parts installed on the aircraft.
Findings
The investigation established that the inability to fully extend the landing gear was due to the loss of hydraulic fluid from the nose gear actuator shaft seal. The source did not specify any other causal factors or contributing elements.