FAA Issues AD on AS 350/AS 355 hydraulics

The FAA has issued an airworthiness directive (AD) for the Eurocopter AS 350B/BA/B1/B2/B3/D and AS 355E Squirrel light helicopters, requiring replacement of the hydraulic fluid at a specified interval when operating in cold weather. The amendment is prompted by reports of ice forming due to condensation in some parts of the hydraulic system. The formation of ice could cause unintended movement of the flight controls and subsequent loss of control of the helicopter, the FAA stated. Operators must replace the hydraulic fluid if the outside air temperature is forecast to be lower than 5 degrees F and the hydraulic fluid has not been replaced within the past 100 hours time-in-service or within the past 30 days (whichever occurred first).