Beech 65-A90 N129LA accident near Dekalb, Illinois

Probable cause

The collapse of the landing gear during landing due to the company's improper maintenance practices and the pilot's decision to take off with an overextended landing gear strut.

NTSB analysis

The Beech King Air had undergone maintenance that included a landing gear disassembly and inspection in preparation for the airplane's sale. Following the landing gear inspection, the left main landing gear strut was overfilled to an extension that exceeded maintenance specifications due to the strut not being able to maintain the manufacturer's specified pressure/extension. In preparation for a maintenance test flight relating to engine throttle adjustments, an asymmetric left fuel load was used by the pilot in an attempt to compress the overextended strut at an airplane weight that was less than the maximum gross weight of the airplane. Upon completion of the flight, the pilot returned to the departure airport where he attempted a landing with a left quartering tailwind and with the airplane flaps fully retracted. The airplane touched down between the runway centerline and right side of the runway. The left main landing gear then collapsed, and the airplane veered off the left side of the runway. The pilot, who was the also the president of the company that performed the landing gear inspection and other maintenance items, reported that the landing gear was a Beech Queen Air part. Examination of the left main landing gear cylinder revealed that it separated at the lower joint above the upper torque knee. The joint exhibited corrosion and paint on its mating surface. The braze coverage in this area was noted to be acceptable with no anomalous voids. The separation was consistent with torsional overload. The examination also revealed that the landing gear shock assembly was a Beech Queen Air part that was not approved for installation on Beech King Air airplanes.

Text from the NTSB. Open the NTSB docket for CEN10LA143 for the full record.