NTSB Factual Report

On January 9, 2004, approximately 1530 central standard time, a Piper PA-23-160 twin-engine airplane, N3289P, was substantially damaged following a partial loss of engine power on takeoff from Hicks Airfield (T67), near Forth Worth, Texas. The commercial pilot and the two passengers were not injured. The airplane was owned and operated by a private individual. No flight plan was filed and visual meteorological conditions prevailed for the personal flight conducted under 14 Code of Federal Regulations Part 91.

In a written statement, the pilot reported that prior to departure he filled both fuel tanks (for a total of 72 gallons) and performed a pre-flight inspection, which included sumping both fuel tanks. No debris or water was noted.

The pilot, along with his two passengers, boarded the airplane, started both engines, and taxied to the run-up area located near the end of Runway 32 (a 3,740 feet long by 60 feet wide asphalt runway). Utilizing the aircraft checklist, he increased RPM on both engines, and performed a check of the magnetos, propeller governors, carburetor heat, and alternators. No anomalies were noted and both engines ran "well and smooth." Additionally, a scan of the engine instruments revealed no discrepancies.

The pilot taxied the airplane onto the runway, slowly increased power on both engines to full RPM, and began the take-off roll. When the airplane's airspeed increased to 85 miles per hour (mph) (red-line on the airspeed indicator), he rotated, and the airplane began to climb. When the airspeed increased to 95 mph (blue-line on the airspeed indicator), the airplane suddenly yawed to the right and the airspeed decreased. The pilot said it, "felt like my right engine stopped working." In 3 to 4 seconds, the airplane was over a row of hangers. The pilot lowered the nose of the airplane in an attempt to gain airspeed. But, there was insufficient altitude to clear the hangars and subsequently the airplane collided with one of them, then impacted two parked aircraft.

A Federal Aviation Administration (FAA) inspector performed an on-scene examination of the airplane on the day of the accident. According to the inspector, the airplane came to rest upright at the base of a row of hangars. The left wing remained attached to the airframe, and the right wing, which also exhibited impact damage, had separated and was located to the right of the fuselage. The engine had also separated and came to rest upside down, forward of the right wing.

Examination of the right engine revealed that the mixture control cable was disengaged from the carburetor mixture control arm and the cotter pin used to secure the tension nut on the mixture cable was not installed. The mixture control arm was in the idle cut-off position. The airplane owner was instructed to recover the wreckage and secure it in his hangar for future examination.

An engine examination was scheduled January 21, 2004, at the owner/operator's hangar facility. Shortly after the investigative team arrived, a decision was made to transport the engine to another facility for examination.

Examination of the engine revealed that when the propeller was removed, a front crankshaft seal had not been installed, and the propeller attachment nuts were not properly secured. The engine case, cylinders, and accessories were coated with engine oil.

The crankshaft flange displayed aft bending on one side and two of the propeller flange bushings were displaced. One of the propeller blades was bent aft approximately 3 degrees, and exhibited front chordwise scoring and polishing. The second blade was bent aft approximately 10 degrees, and exhibited chordwise scoring near the tip.

The engine was manually rotated at the crankshaft flange, and valve train continuity and compression were established on each cylinder. During the compression check, spark was produced on the bottom ignition leads. The lower spark plugs were removed and examined. Examination of the plugs revealed excessive carbon and lead deposits, and electrode erosion beyond the limits specified in the Champion Spark Plug Wear Guide P/N AV-27.

The inlet and outlet lines to the engine driven fuel pump had separated.

In addition, there were no case match-numbers or crankshaft numbers. The engine serial number stamped on the crankcase did not match the engine serial number stamped on the engine data plate.

The exhaust system had several screw-type clamps installed, which supported heat shrouds that had sustained chaffing damage and holes. A stainless-steel clamp was installed on the #3 exhaust stack, which partially covered a pencil-sized hole.

The engine was then transported to Air Salvage Of Dallas (ASOD), Lancaster, Texas, where a test-run was conducted on January 22, 2004, under the supervision of the Safety Board.

Prior to the engine run, timing was verified, the cylinders were inspected with a lighted borescope, and the spark plugs were removed and inspected. The fuel line to the carburetor had separated in the accident sequence, and a dead bee was found in the fuel inlet screen. Additionally, the propeller was reinstalled, an engine mount was replaced, the oil dipstick housing was replaced, and throttle, mixture, and propeller control cables were installed. Due to impact damage, the engine driven fuel pump was bypassed. Five and half quarts of fuel were added to the engine and a gravity fuel source was utilized.

The engine started and was operated at various power settings up to 1,500 RPM. Due to excessive vibrations created by the bent crankshaft and propeller, the engine was not tested above this speed. The engine ran continuously and without hesitation for approximately 10 minutes. The propeller was actuated and operated normally. Both magnetos were checked and no anomalies were noted. The engine driven fuel pump produced suction and exhaust, and oil was noted draining from the forward crankshaft area.

The mixture control swivel, stud, and a segment of the mixture control cable were examined at the NTSB's Material's Laboratory, Washington DC, on April 12, 2004. According to a Safety Board metallurgist, examination some of the components indicated wear damage. But, the mixture control cable did not exhibit any longitudinal gouge marks or wear damage that would have been consistent with it being separated during the accident sequence.

During the initial engine examination, the owner/operator reported that he had performed the engine's overhaul, but did not replace the bearings. According to engine manufacturer, the bearings are a mandatory replacement item during engine overhaul.

A weight and balance computation was made using the airplane's original factory weight and balance. Based on the calculations, the airplane was within weight and balance limits.

The pilot reported a total of 377 flight hours, of which, 41 hours were in twin-engine aircraft. He also reported a total of 10 hours in the same make and model airplane.

The weather at Hicks Field was reported as clear skies, and wind from 350 degrees at 11 to 13 knots.

NTSB Probable Cause

The pilot's failure to maintain control and the partial loss of engine power as a result of an improperly installed mixture control linkage.