Cessna Stationair/Turbo Stationair 7/8
Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 100; Flight Crew Total 1650; Flight Crew Type 200
Confusion; Human-Machine Interface; Troubleshooting
Aircraft Equipment Problem Critical; Inflight Event / Encounter Loss Of Aircraft Control
Flight Crew Overcame Equipment Problem; Flight Crew Regained Aircraft Control
Aircraft
Prior to departing from the water [in the amphibious C208]; I performed all Before Takeoff Checklists including a full flight control check. All items checked OK; including the flight controls which were noted to be free and correct. As I began the takeoff I brought the yoke full aft until the nose rose to its maximum pitch up attitude. At that time I relieved back pressure to allow the nose to drop so the aircraft could accelerate on to 'the step' As the aircraft accelerated to liftoff speed I began to ease back on the yoke to initiate a climb. At this time I noted that a significant amount of force was needed to move the yoke aft of its neutral position the aircraft became airborne. I decided to continue my climb due to insufficient water remaining to touch down and abort the departure. Once airborne the aircraft flew normally [except for] the need for an ample amount of trim to relieve the elevator pressure. At the time I thought this was due to an aft Center of Gravity (CG); or possibly a rope from the floats had come loose and was fouled on the elevator although the CG had been checked within limits before departure and was near the aft end of the envelope; still; however; within legal limits. The [rest of the] flight was uneventful and I had no knowledge of any mechanical malfunction. The aircraft flew normally after the initial climb and the flaps were retracted. Once at cruise altitude I checked that all ropes on the floats were secure.During landing I noted a significant amount of trim was needed to relieve the elevator pressure and I chose to keep the airspeed higher than normal on approach to ensure sufficient controllability. Upon touchdown I realized the yoke's range of motion was limited to full forward and just shy of neutral. After I shut down I performed an exterior post flight and could not see any damage to the control surfaces. To clarify; I had no knowledge of any flight control failure or malfunction until I had reached my destination. The need for excess trim could have been caused by a number of factors and was not significant enough to warrant a diversion to another airport or to dictate any type of emergency. At no time was the aircraft out of my control nor did I feel there was danger present to my passenger or myself. There was sufficient elevator travel remaining that the aircraft flew normally once the flaps were retracted. I believe the elevator torque tube link to the rudder gust lock snapped when I pushed the yoke forward during the takeoff run. The remainder of the flight did not require enough elevator back pressure to uncover this failure until I landed as this was the only other time during flight the yoke needed to be brought back to such a position. Upon inspection maintenance discovered the elevator torque tube link for the rudder gust lock had corroded and failed. This caused the link to fall below its normal position hindering the elevators' range of travel due to the link making contact with the aft bulk head instead of traveling through its hole in the bulk head. Effective elevator travel was from full forward to just shy of the neutral position.
The pilot of an amphibious C-208 suffered partial loss of elevator control shortly after becoming airborne. The flight was continued to destination with only abnormal trim being obvious. Only during and after landing did it become obvious that elevator movement was restricted to roughly neutral to full down. Only 'up' trim had allowed the airplane to maintain the desired pitch attitude during the flight.