What happened
An airline transport certificated pilot was preparing to land a multiengine, retractable gear airplane when the right main landing gear failed to extend. As the pilot lowered the landing gear, there was no cockpit indication that the right main gear had reached the extended position.
The pilot attempted emergency gear extension procedures, which included utilizing the emergency blow-down system; however, the right main gear remained unextended. The pilot proceeded to land with only the left main landing gear and the nose gear extended. During the landing roll, the pilot shut down the right engine. As the aircraft decelerated, the right wing and fuselage made contact with the runway surface.
The investigation
A post-accident examination of the aircraft revealed scuffing and scraping damage to the underside of the right aileron and the right wing. The right main landing gear strut was found to be fully compressed. While the gear extension and retraction components appeared undamaged, an FAA inspector discovered that the right gear hydraulic actuator contained water contamination. Given that the temperature at the accident location was -2 degrees F, it was determined that the actuator had likely frozen.
Findings
- The right main landing gear failed to extend due to a frozen hydraulic actuator.
- Water contamination within the hydraulic actuator caused the failure in freezing temperatures.