History of Flight
On November 26, 2011, at approximately 1333 eastern standard time, a Cessna 177RG, registration N5AW, departed Knoxville Downtown Island Airport (DKX) en route to Northwest Florida Beaches International Airport (ECP). The flight was conducted under 14 CFR Part 91 with an instrument flight rules flight plan. Visual meteorological conditions prevailed.
While in cruise flight at 4,000 feet, the pilot contacted Atlanta air route traffic control and declared an emergency due to low engine oil pressure. He requested radar vectors to the nearest airport and was given a heading of 130 degrees to West Georgia Regional Airport (CTJ). The pilot reported he could not reach the airport and intended to land in a field. Radar contact was subsequently lost, and no further transmissions were made.
A witness observed the airplane flying at low altitude over his home. The airplane executed a sharp banking turn, apparently attempting to land in a corn field, but collided with a tree line at the end of the field and caught fire. The witness ran to the site and saw one passenger walking outside the airplane, severely burned but alert. Emergency responders arrived shortly thereafter.
Personnel Information
The pilot, aged 55, held a private pilot certificate with ratings for airplane single-engine land and instrument airplane. His last FAA third-class medical certificate was issued November 11, 2011, with a limitation for near vision. On his last medical application, he reported 975 total flight hours and 50 hours in the previous six months. His logbook was destroyed in the post-crash fire, so current flight hours and last flight review could not be verified. An aviation insurance application dated April 27, 2011, indicated 915 total flight hours and 602 hours in make and model.
Aircraft Information
The aircraft, serial number 177RG-0320, was a four-seat, high-wing, retractable-gear airplane manufactured in 1972. It was powered by a Lycoming IO-360A1B6 180-horsepower engine with a Hartzell constant-speed propeller. An annual inspection was completed on January 1, 2011, at a tachometer reading of 1034.2 hours, with an airframe total time of 5940.7 hours and engine time since major overhaul of 813.9 hours. The tachometer and Hobbs meter were damaged precluding current readings.
Maintenance records from Zephyr Aircraft Engines indicated the engine had a cracked crankcase repaired on September 8, 2006; the crankcase, through bolts, front main bearing, crankshaft gear bolt, and oil pressure relief ball were replaced. The connecting rods were not removed from the crankshaft at that time, and no cylinder work was performed.
Meteorological Information
The reported weather at CTJ, located about 11 miles southeast of the accident site, at 1335 was: wind 170 degrees at 10 knots gusting to 15 knots; visibility 10 statute miles; scattered clouds at 2,900 feet, broken at 3,600 feet, overcast at 5,500 feet; temperature 20°C; dew point 16°C; altimeter 30.19 inches of mercury.
Wreckage and Impact Information
The accident site was approximately 11 nautical miles northwest of CTJ. The airplane came to rest in a flat attitude on a heading of about 006 degrees, within trees at the north end of a cleared field. The fuselage was consumed by post-crash fire. Both wing assemblies were fire-damaged, and all flight control surfaces were accounted for. The engine remained attached to the firewall and was fire-damaged.
The cockpit and cabin were fire-damaged; all instrumentation was unreliable. Flight controls were fire-damaged, with only control cables remaining. The fuel selector valve was not observed; the surrounding area was consumed by fire.
The left wing's inboard section remained attached; the outboard six feet were separated. The left aileron and flap remained attached; the flap actuator measured 2.2 inches (approximately 10 degrees extension). Both aileron control cables were separated in tension overload. The empennage and stabilator were burned; control continuity was established from empennage to cockpit.
The propeller assembly remained attached to the crankshaft and was fire-damaged. The propeller was in a low pitch position and did not show signatures of rotation at impact; the spinner was crushed on one side. All three blades exhibited discoloration from fire. Blade A had no damage; blade B curved aft about 20 degrees; blade C bent aft about 45 degrees, eight inches from the hub.
Engine examination revealed left and right crankcase halves fractured between the #1 and #2 cylinder base pads. The #2 crank journal was visible through the fracture; no connecting rod was observed on the journal. Disassembly showed #1 connecting rod lower bolt nut backed off about 1/8 inch; the upper nut was removed with little effort. One rod bolt was visibly stretched. Rod bearings exhibited radial scoring and thermal discoloration. The #1 rod journal had light radial scoring and thermal discoloration. The #2 rod end had separated from the crank journal and was impact-damaged; portions of the rod cap, bolts, and one nut were recovered. The #2 crank journal was discolored with bearing material. #3 and #4 connecting rods remained attached with tight nuts; their bearings exhibited heavy radial scoring. Associated crank journals showed scoring and thermal discoloration.
Crankshaft front and center main bearings were undamaged; oil was present on the front main bearing. Rear main bearings had light scoring and discoloration; the journal had thermal discoloration. Tappet faces showed wear marks consistent with camshaft lobes. Oil pump gears were undamaged.
The fuel injector servo was fire-damaged; the inlet screen had no contaminants. The flow divider diaphragm was melted. Fuel nozzles were unobstructed. The engine-driven fuel pump was partially consumed. No fuel was observed in engine fuel components. The aircraft fuel strainer was not observed. Magnetos were thermally damaged and could not be rotated. Spark plugs were normal, except #2 bottom plug was oily. The ignition harness, starter, and alternator were fire-damaged. The vacuum pump was fire-damaged; the plastic drive coupling was burned. Metallic flakes were found in the oil suction screen. The oil filter was charred with no contaminants between folds. The oil cooler was partially separated with thermal discoloration; hoses were fire-damaged.
Medical and Pathological Information
An autopsy of the pilot on November 28, 2011, determined the cause of death as smoke and soot inhalation. Forensic toxicology by the FAA Bioaeronautical Sciences Research Laboratory detected no ethanol in liver or muscle; rosuvastatin was detected in liver and blood.
Testing and Research
Examination of the #2 cylinder rod cap and bolts revealed the cap fractured through the middle and flattened. The bolt fractured through threads near the grip, flush with the first engaged thread in the nut. Optical microscopy showed a smooth, silky fracture surface except for a semi-circular area with microscopic roughness. The fracture followed thread roots. Directional features on the nut side of the bolt indicated a counterclockwise torsional force consistent with shear dimples. Bearing shells for #3 and #4 cylinders showed severe abrasive wear, some worn through to steel backing, with dark discoloration and areas of melting, indicating exposure to elevated temperatures.