NTSB Factual Report

On August 14, 2014, about 1807 central daylight time, a Cessna T206H, N1229M, was substantially damaged following a partial loss of engine power and forced landing near Wiggins, Mississippi. The private pilot and two passengers received minor injuries. The airplane was operated by the pilot under the provisions of 14 CFR Part 91, and no flight plan was filed. Day, visual meteorological conditions prevailed for business flight that originated at Sherman, Texas (GYI) and was destined for Daytona Beach, Florida (DAB).

According to the pilot, the flight was in the vicinity of Hattiesburg, Mississippi when he elected to change his landing destination to Mobile, Alabama (MOB) to refuel and have dinner. After descending to 2,500 feet above mean sea level (MSL), he leveled the airplane and advanced the throttle, but observed no response from the engine. He could not recover engine power, although the propeller continued to spin. The throttle "felt very loose." He maneuvered the airplane toward the nearest airport; however, there was not sufficient altitude to reach the airport. The airplane collided with trees before coming to rest in a farm field.

An inspector with the Federal Aviation Administration responded to the accident site and examined the wreckage. He confirmed substantial damage to both wings and extensive damage to the fuselage. The engine broke free from its mounts during the impact sequence. The wreckage was recovered and moved to a storage facility at Baton Rouge, Louisiana for a more detailed examination.

The wreckage was examined on August 20, 2014, under the supervision of an inspector with the FAA. The following observations were noted. The propeller remained attached to the crankshaft flange. The propeller spinner was partially crushed. The lower engine cowl and the exhaust tailpipe were partially crushed. The throttle, mixture and propeller control cables were pulled from the firewall. The engine cowlings were removed and the engine was suspended from a lift so it could be partially disassembled to facilitate the examination. The engine oil dipstick indicated 8 quarts.

The engine was rotated by turning the propeller and continuity of the crankshaft to the rear gears and to the valve train was confirmed. Compression and suction were observed on all engine cylinders. The interiors of the cylinders were examined using a lighted borescope and no anomalies noted other than oil in the right side cylinders.

The propeller remained attached to the crankshaft flange. The propeller spinner was partially crushed. One propeller blade remained straight. Another blade exhibited a bend of about 20 degrees at the tip and scratches on the forward surface. The remaining blade was loose in the propeller hub and was bent about 45 degrees near mid-span. The propeller governor remained attached to the engine. The governor control arm assembly was impact-separated from the governor. The propeller control cable remained attached to the governor control arm. The governor was removed and the governor oil screen was observed absent of debris.

The fuel injector servo remained attached to the engine. The throttle control cable remained attached to the servo throttle control arm. The control arm was against the idle stop pin on the servo and the pin was bent about 45 degrees. The portion of the control cable which was normally clamped just forward of the upper right firewall was observed forward of and not clamped in the clamping device. The pilot reported that the cockpit throttle control "felt very loose" when he attempted to add power after a descent. The mixture control cable remained attached to the servo mixture control arm. The control arm was observed against the idle cut-off stop.

The servo was removed and partially disassembled. The servo fuel inlet screen was absent of debris. The fuel regulator section safety wire was intact and the brass plug was secure. The rubber diaphragms were intact. The flow divider remained attached to the engine and the associated hoses and lines were secure. The flow divider was partially disassembled and the rubber diaphragm was observed intact. The fuel injector nozzles were unobstructed.

The engine-driven fuel pump remained attached to the engine and the associated fuel lines remained attached and secure. The pump was removed and produced water when a hose to the fuel inlet was submerged in water and the pump was rotated using an electric drill. Liquid with and odor consistent with that of aviation gasoline was observed in all engine compartment fuel hoses from the firewall to the fuel flow divider and in the engine driven fuel pump, fuel injector servo and the flow divider. The aircraft fuel strainer screen on the firewall was absent of debris.

Both magnetos remained attached to the engine and no damage was noted. Both produced spark from all ignition towers when rotated by hand.

All spark plugs were removed for examination. The numbers 2 (top and bottom), 4 (top and bottom), 5 (bottom), and 6 (top and bottom) had undamaged electrodes and were normal in color. The numbers 1 (top and bottom), 3 (top and bottom), and 5 (top) plugs had undamaged electrodes and were oil-soaked. The ignition harness exhibited substantial impact-related damage.

The turbocharger remained attached to the engine but was separated from the exhaust system. No damage was noted to the turbocharger and it was not removed. The associated oil lines remained attached and secure. The turbine wheel was oily (the engine was lying on its right side). The turbine and compressor wheels rotated freely by hand and no scoring was noted in the turbine or compressor housings. The sloped controller was impact-separated from the firewall. No damage was noted and the hoses remained attached. The manifold pressure relief valve remained attached to the induction system and no damage was noted. The valve operated freely by hand. The exhaust bypass valve controller remained attached to the turbocharger and was impact damaged. No damage was noted to the exhaust bypass valve.

According to the operator, an annual inspection of the airframe and engine was completed on October 1, 2013, at 507 hours total airframe time.

NTSB Probable Cause

A loosening of the engine throttle cable from its support clamp during flight, which resulted in a loss of throttle control.