Saturday, March 31, 2012

Frozen Brakes

Heavy Rain Can Cause Frozen Brakes
          It is reminded that carbon disc brakes can retain moisture from exposure to heavy rain or washing; leading to the possibility of frozen brakes upon landing. 
           Climate conditions well above freezing at departure are irrelevant if moisture levels in the brakes are sufficient to freeze during cold soak at altitude.
      A Bombardier airplane experienced damage during a landing from a blown MLG tire. The airplane was exposed to a significant amount of rainfall apprx. 12 hours before the airplane departed from a dry runway. As the airplane climbed to high altitude in sub-freezing conditions, moisture in one of the brakes froze causing the wheel to lock on landing.
         FAA reminds maintenance personnel to protect wheels and brakes from direct washing spray and inform flight crews if aircraft or landing gears were washed recently.
    Flight crews should refer to AFM procedures for brake applications during taxi to warm the brakes to evaporate moisture prior  to takeoff. The procedures can be found in Section III – Operating Procedures, Normal Procedures, Contaminated Runway

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