The Airframe and Propulsion & Services (ACE-118W) of the Wichita Aircraft Certification Office (ACO), located in Wichita, Kansas, submitted the following article. (The article is published as it was received.)

Service Difficulty Reports are being received regarding leaks in the landing gear down hydraulic line in the cockpit on Cessna 210 aircraft. In one case this resulted in an in-flight loss of all hydraulic fluid.

With the loss of all hydraulic fluid, the emergency landing gear hand pump would not lower the gear.

The aircraft was then forced to land gear up. An investigation revealed the movement of the aileron control cable from the pilot’s control wheel had worn a hole into the landing gear down hydraulic line. This line is located in the area of the pilot’s right rudder pedal.

It was found that the gear down hydraulic line was not adequately supported and was repositioned against the aileron cable. Since the hydraulic line is located close to the pilot’s feet, the hydraulic line could have been inadvertently repositioned against the aileron cable by the foot of the pilot. This situation would then allow the aileron cable to wear into the hydraulic line and cause the failure of the landing gear system.

Owners, operators, and maintenance personnel should inspect the landing gear hydraulic lines of Cessna 210 aircraft in the forward cockpit area near the rudder pedals for wear damage or leaks. If the hydraulic lines are in close proximity to the aileron cables, the lines should be repositioned to provide adequate clearance to prevent interference between the hydraulic lines and the aileron control cables. The hydraulic lines should be positioned to provide sufficient clearance for the pilot’s feet during operation of the rudder pedals. It is recommended that this inspection be completed within the next 10 hours of operation and be repeated after every 100 hours of operation or 12 months, whichever occurs first.