What happened
A 14 CFR Part 135 commuter air carrier passenger flight was en route to its destination when the crew encountered significant landing gear issues. After arriving at the destination airport and performing the required before-landing checks, the pilot discovered that the left main landing gear would not extend. While the nose gear and right main landing gear successfully extended, they failed to retract.
The flight crew attempted to use the emergency landing gear extension procedure, but these efforts were unsuccessful. Due to the malfunction, the pilot requested and received clearance to return to the departure airport. Upon returning to the origin, the crew again attempted the emergency landing gear extension, which also yielded negative results. The aircraft subsequently completed a landing on the runway, which caused minor damage to the airplane. All occupants, including two crewmembers and two passengers, were not injured.
The investigation
Following the incident, maintenance personnel performed an examination of the aircraft. The inspection revealed that the main landing gear sequencing valve failed, though the specific reason for this failure could not be determined.