Cessna 210 N2157S accident near Houston, Texas

Probable cause

The failure of a hydraulic fluid line, which caused a loss of hydraulic pressure to the landing gear extension system and resulted in the partial collapse of the right main landing gear during touchdown.

NTSB analysis

During approach, the pilot moved the landing gear position handle to the down position, the hydraulic gear motor started, and the landing gear started to extend. The pilot did not receive a green gear down indicator light, and he visually confirmed that the landing gear did not appear to be fully extended. The pilot completed a number of checklist items including a "G maneuver." All attempts to extend the landing gear did not work, so the pilot prepared for a gear-up landing. During touchdown, the left main landing gear and the nose landing gear remained extended but the right main landing gear collapsed, and the airplane veered off the right side of the runway. The mechanism for landing gear extension and retraction in the airplane is accomplished by hydraulic actuators powered by an electrically driven hydraulic power pack or by use of an emergency extension hand pump. During the postaccident examination of the hydraulic system, a hydraulic line for the landing gear was found separated from its respective fitting, which would have resulted in a loss of hydraulic pressure. The separated line and adjacent wheel well area were found saturated with hydraulic fluid. The manufacturer’s maintenance manual requires that all rubber hydraulic lines should be replaced each 1000 hours or 5 years. During a review of the airplane’s maintenance records, there were no annotation found that indicated that rubber hydraulic lines has been replaced within the manufacturer’s recommended interval.

Text from the NTSB. Open the NTSB docket for CEN10LA389 for the full record.