What happened
On March 2, 2010, a Beech 65-A90 (King Air), registration N129LA, was performing a maintenance test flight to check engine performance and throttle settings. The flight originated from DeKalb Taylor Municipal Airport (DKB) and remained in the local traffic pattern. During the landing on runway 09, the pilot performed a touchdown that was described as normal, but during the landing roll, the left main landing gear wheel began to vibrate.
Believing the tire might be flat, the pilot applied reverse thrust and braking. As the aircraft slowed, the left main landing gear collapsed, causing the aircraft to skid to a stop and strike the propeller. The aircraft ended up off the left side of the runway. The pilot and a passenger were not injured.
The investigation
Investigators found that the left main landing gear strut had been serviced four times prior to the accident. After each service, the strut would lose pressure overnight while retracted. To address this, the strut was inflated to a 6-inch extension, which was approximately twice the recommended extension. In preparation for the maintenance test flight, the pilot used an asymmetric fuel load—filling the left wing while leaving the right wing nearly empty—in an attempt to compress the overextended strut.
An examination of the left main landing gear shock absorber assembly revealed that the part (number 50-810002) was a Beech Queen Air part, which was not approved for installation on Beech King Air airplanes. This specific part was designed with dampening rates for the loads experienced by Queen Air 65 series aircraft.
Technical analysis of the components showed that the separation at the brazed joint was consistent with torsional overload. The joint also exhibited evidence of corrosion and paint on the mating surface, though the braze coverage itself was found to be acceptable with no anomalous voids.