Incident Sequence
On 9 April 2007, at 1703 Western Standard Time, a Beech Super King Air 200 aircraft, registered VH-SGT, experienced a collapse of its main landing gear upon landing at Perth Airport. Approximately two hours earlier, the aircraft had departed Perth on a charter flight to Mount Hale, Western Australia. Shortly after takeoff, the landing gear system malfunctioned: the main wheels and nose gear became jammed and could not fully retract when the pilot selected them up.
Emergency Actions
The pilot executed the emergency checklist from the Aircraft Flight Manual but was unable to retract or extend the gear using either the automated control or the manual emergency system. The pilot then requested assistance from a passenger to operate the manual emergency extension system. Despite additional force applied to the lever, the landing gear remained jammed. The pilot contacted air traffic services and sought help from company engineering personnel to visually assess the gear position. Two aerodrome passes were completed during troubleshooting, with the pilot maintaining radio contact throughout. Following the flyovers and a holding period over Rottnest Island at 5,000 feet for approximately two hours, the pilot returned to Perth Airport.
Landing and Damage
With the gear still jammed in a partially retracted position, both left and right main landing gear assemblies collapsed after the aircraft touched down on Runway 24. The aircraft sustained substantial damage. Airport Rescue and Fire Fighting services and other relevant agencies had been alerted and were standing by. No injuries were sustained by the pilot or the nine passengers on board.
Investigation Findings
The investigation revealed that two major system components had failed, which could have prevented the landing gear from properly retracting after takeoff. Contributing safety factors included: the left torque tube support bearing had not been lubricated and had seized due to the accumulation of dirt and grit contaminants migrating from the external service environment; and the geared components within the right main landing gear actuator prematurely failed. An additional safety factor was that the aircraft manufacturer's maintenance manual contained insufficient instruction or guidance for lubrication of the landing gear torque tube support bearings. The investigation was unable to determine which failure was the principal contributor to the event, nor could it conclusively establish why the actuator components failed prematurely. The lower thrust bearing within the right main landing gear actuator had been correctly installed.