MARANA, AZ, USA
N7156T
PIPER PA-23-250
THE PILOT WAS BEGINNING A FLIGHT TO TRANSPORT MARIJUANA IN DUFFLE BAGS. SHORTLY AFTER TAKEOFF THE RIGHT PROPELLER BEGAN TO SEPARATE FROM ITS MOUNTING FLANGE. THE PILOT TURNED THE AIRPLANE TOWARD THE AIRPORT, FEATHERED THE WRONG PROPELLER AND BEGAN TO THROW OUT THE DUFFLE BAGS. THE AIRPLANE COLLIDED WITH A TREE, WIRES, AND A PRIVATELY OWNED RESIDENCE. TWO PERSONS IN THE RESIDENCE SUSTAINED MINOR INJURIES. THE POST ACCIDENT WRECKAGE EXAMINATION REVEALED THAT THE PROPELLER MOUNTING STUDS SAFETY WIRE WAS BROKEN AND THREE OF THE SIX PROPELLER MOUNTING STUDS WERE BROKEN. THE REMAINING MOUNTING STUDS HAD BACKED OFF. THE RIGHT ENGINE OIL SYSTEM CONTAINED EXTENSIVE METAL PARTICLES AND THE PROPELLER GOVERNOR OIL SCREEN WAS ALTERED TO ALLOW UNFILTERED OIL FLOW.
On August 30, 1995, at 0553 hours mountain standard time, a Piper PA-23-250, N7156T, collided with a tree, wires, and a privately owned residence about 2.5 miles northwest of Avra Valley Airport, Marana, Arizona. The pilot was beginning a visual flight rules (VFR) flight to an undetermined destination and was returning to the airport after sustaining a loss of power on the right side engine. The airplane, owned and operated by the pilot, was destroyed by impact forces and the postimpact fire. The certificated commercial pilot, the sole occupant, received severe burn injuries and died on September 14, 1995. The on-scene postcrash investigation was conducted by two airworthiness inspectors from the Federal Aviation Administration (FAA), Scottsdale [Arizona] Flight Standards District Office. An inspector reported that witnesses stated the engine lost power shortly after departing the airport. The witnesses also said that while returning to the airport, several duffle bags were "thrown out" of the airplane before it struck the tree. Examination of the recovered duffle bags revealed a substantial quantity of marijuana. The inspectors found some airplane maintenance logbooks at the accident site. Examination of the logbooks revealed that there were no maintenance entries made after the airplane was imported to the United States in 1990. Further investigation and search for current logbooks were unsuccessful. A witness told a National Transportation Safety Board investigator that he often saw the pilot doing maintenance on various aircraft. An FAA inspector stated that other witnesses reported seeing the pilot working on the accident airplane. The pilot did not hold a mechanic certificate. Safety Board investigators conducted a telephone interview with the sales manager of Double Eagle Aviation, Haskell, Oklahoma, on November 10, 1995. The sales manager reported that he sold the airplane to the pilot, in a cash transaction, on August 25, 1995. According to Double Eagle records, at the time of the sale, the airplane's annual inspection was due on March 1, 1996. The airplane accrued 5,732 flight hours and the engines accrued 1,010 and 1,802 hours, left and right, respectively, since major overhaul. The on-site investigation of the scene revealed that the cabin/cockpit area was incinerated by the postcrash fire. The FAA inspectors examined the engines and propeller assemblies at Air Transport, Phoenix, Arizona, on September 2, 1995. Both engines sustained extensive fire damage and their respective accessories could not be functionally tested. Left Engine Examination: Continuity of the engine gear and valve train assemblies was established. Thumb compression was noted on all cylinders when the crankshaft was rotated. The number 6 cylinder head was melted and its piston was exposed. The spark plugs, except the number 2 lower spark plug, displayed normal operating signatures. The number 2 lower spark plug was oil soaked. The oil was found free of contaminates. The inspectors found the left propeller blades in a feathered position. Right Engine Examination Continuity of the engine gear and valve train assemblies was established. Thumb compression was noted on all cylinders when the crankshaft was rotated. The main engine oil screen contained extensive metal particles. Disassembly examination of the engine showed that the cylinders, pistons, and piston rings displayed normal operating signatures. The forward main bearing display edextruded bearing material and wear patterns between the crankshaft thrust face and the crankshaft surface. Some connecting rod bearings displayed high temperature distress. The upper spark plugs displayed normal operating signatures. The numbers 1 and 2 lower spark plugs were oil soaked and the remaining lower spark plugs displayed some lead deposits. The oil, however, contained extensive metal particles. The right propeller blades were near the low pitch, high rpm, position. One propeller blade was bent toward the face side and displayed many chordwise scuffing signatures; the remaining blade displayed minor chordwise scuffing signatures. Neither blade displayed any "S" twisting deformation. The right propeller assembly was found loose on the crankshaft mounting flange. Three of the six studs were found sheared; the remaining studs were found "back-off" from the crankshaft mounting flange. The mounting flange studs' safety wire was found broken. Examination of the broken safety wire showed characteristics of a tensile overload fracture. The mating faces of the engine output shaft and the propeller extension displayed metal transfer signatures. A 1/2-inch hole was found drilled through the propeller governor screen. According to the Lycoming representative, this alteration allowed full unfiltered oil flow and is not an authorized repair procedure. The Maricopa County Medical Examiner reported that the pilot expired on September 14, 1995, due to complications of thermal burns. Toxicology examinations were not conducted.
the pilot's poor installation of the propeller which allowed the propeller to become loose, and the pilot's improper emergency procedure by feathering the wrong propeller.
Source: NTSB Aviation Accident Database
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