NTSB Identification: CEN11IA108
Nonscheduled 14 CFR Part 91 Subpart K: Fractional
Incident occurred Monday, December 13, 2010 in Columbus, OH
Probable Cause Approval Date: 03/20/2012
Aircraft: PIAGGIO P180, registration: N140SL
Injuries: 4 Uninjured.

NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.

During the airplane's descent, the yaw damper disengaged while the autopilot remained on. When the flightcrew checked the flight controls for freedom of control, the ailerons, elevator, and rudder were found to be frozen in place. The flightcrew exerted enough pressure until the controls broke free with a “snap.” The flight controls remained stiff for the remainder of the flight. The temperature was -9 degrees C at the destination. Following a normal approach and landing, the flight controls and nosewheel steering became inoperative. The flightcrew used differential power and braking to taxi to the ramp. A postflight examination by maintenance personnel revealed ice in the area of frame 36 and around the primary flight control cables and pulleys in that area. An examination of the fuselage drain holes showed no obstructions and the airplane was returned to service. An emergency airworthiness directive was subsequently issued that advised of three incidents and that required inspection of the fuselage belly and testing of the fuselage drain holes.

The National Transportation Safety Board determines the probable cause(s) of this incident to be:

The failure of water to properly drain through the fuselage drain holes, thus becoming trapped and freezing around the flight control cables, which resulted in the loss of control authority to the airplane's ailerons, elevator, and rudder.

Full narrative available

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