Final Report: Faulty downlock plates caused gear collapse

 - June 9, 2008, 9:51 AM

Hawker Beechcraft King Air 200, Leonardtown, Md., Oct. 12, 2006–The NTSB said the King Air’s gear collapse on landing was caused by the airplane manufacturer’s inadequate landing-gear downlock plate maintenance orientation information, and the resulting disengagement of the main landing gear.

Immediately after the King Air touched down at St. Mary’s County Regional Airport, the landing gear warning horn sounded intermittently and the right wing began to “drop.” The right gear collapsed, the airplane then veered to the right and the right propeller struck the runway. No one was injured in the subsequent fire.

Investigation showed that both landing gear assembly downlock plates had been installed with their beveled surfaces facing aft, but they should have been facing forward. As installed, the downlock plates and downlock hook had a mutual contact area of less than 0.05 inch. When correctly installed, the contact area increased to .25 inch.