Cessna 210J N210WS accident near Fort Myers, Florida

Probable cause

The failure of the landing gear hydraulic power pack system to provide sufficient pressure to lock the main landing gear in the down position. Contributing to the accident was the improper maintenance and inspection of the landing gear system, the pilot’s continued operation of the airplane with a known mechanical problem with the landing gear system, and the pilot’s failure to visually verify that the landing gear were down.

NTSB analysis

The pilot stated that the airplane had been experiencing landing gear problems before the most recent annual inspection in April 2013 but that he thought that the landing gear problems had stopped after that inspection and maintenance. During departure, the landing gear failed to retract, and the amber light indicating that the landing gear fully retracted did not illuminate. After the pilot cycled the landing gear, the landing gear retracted, the amber light illuminated, and he continued the flight. The pilot stated that, as he neared his destination, he placed the landing gear handle in the "down" position and felt the "clunk" associated with the landing gear locking into place. He added that he quickly checked his wing mirror and confirmed that the landing gear were down before landing and that the green landing gear down-and-locked light "appeared" to be illuminated on the landing gear console. (The wing mirror can only show the position of the nose landing gear.) The airplane subsequently landed without the main landing gear down-and-locked, slid down the runway, and departed its left side. The left main landing gear hydraulic down lock was not in the locked position. A witness, who was also a mechanic, stated that, when the airplane arrived at the airport, he saw the main landing gear trailing aft during landing but that the nose landing gear were down-and-locked. He asked the pilot if he had looked out his left window to visually inspect the left main landing gear and verify that it was down. The pilot replied that he did not think of that and that no one had ever showed him that.

Examinations determined that the hydraulic power pack that operates the functions of the landing gear was past its useful life and needed to be overhauled. The O-rings within the apparatus were malfunctioning and not providing the pressure needed to lock the main landing gear in the down position. If the pilot had looked out the window to visually verify the position of the main landing gear, he likely would have noticed that it was not in the correct position, and he could have accomplished emergency checklists that might have allowed the main landing gear to lock in the down position.

Text from the NTSB. Open the NTSB docket for ERA13LA398 for the full record.