19991209037239A

(.19) On December 9, 1999, at 1909 central standard time, a Cessna 310N, N5038Q, owned and operated by a private pilot, was destroyed during an in-flight collision with terrain following a loss of control shortly after takeoff from runway 21 (5,399 feet by 100 feet, wet/asphalt) at the Danville-Vermilion County Airport (dnv), Danville, Illinois. Instrument meteorological conditions prevailed at the time of the accident. The instructional flight was operating under the provisions of 14 CFR part 91 and was not on a flight plan. The certified flight instructor (CFI) and private rated dual student were fatally injured. The flight was departing at the time of the accident and the flight's destination is unknown. Witness to the accident had landed on runway 21 about 30 minutes prior to the accident time. The pilot-rated witness stated that the CFI asked him, over the common traffic advisory frequency (CTAF), what the cloud bases were. The witness reported that he transmitted that the cloud bases were 1,700 feet mean sea level (MSL) and the CFI acknowledged the transmission. The witness stated that he also saw the accident aircraft departing on runway 21. The witness reported tha t he heard a, "...whoosh sound and thought an engine failure had occurred..." The witness stated that the aircraft, from an altitude of 100-200 feet above ground level (AGL), started a high rate descent towards the runway, then recovered into level flight for a few seconds, then began a climb which took the aircraft into the clouds. Other witnesses to the accident described an unusual engine sound then seeing the aircraft in a descent, then leveling off, and finally start a climbing turn toward the east into the clouds. A weather observation, taken by an automatic weather observation station-3 (AWOS-3) located on the Danville-Vermilion County Airport, reported the weather eight minutes prior to the accident as: observation time: 1901 CST; wind: 310-degrees at 3 knots; visibility: 2 statute miles; sky condition: partial obscuration, 1,300 feet AGL overcast; temperature: 10-degrees centigrade; dew point temperature: 10-degrees centigrade; pressure: 30.00 inches of mercury. A weather observation station, located at the university of illinois-willard airport, 34 nautical miles from the accident site on a 250-degrees magnetic heading, reported the weather 16 minutes prior to th e accident as: observation time: 1853 CST; wind: 340-degrees at 4 knots; visibility: 2 statute miles; sky condition: light rain, mist, 500 feet AGL overcast; temperature: 9-degrees centigrade; dew point temperature: 9-degrees centigrade; pressure: 29.97 inches of mercury; remarks: surface visibility 2 1/2 statute miles; remarks: ceiling varying between 400-700 feet AGL. Examination of the wreckage started on December 10, 1999, and continued for a period of two days. The wreckage was distributed over an area that measured 300 feet by 150 feet. The initial impact crater was located at 40-degrees 11.235-mintues north latitude, 87-degrees 35.130-mintues west longitude, and was approximately 1-foot in depth. There was burnt soil and vegetation in the initial impact crater. A ground scar, 8 feet wide by 55 feet long, on a 045-degrees magnetic heading, originated from the initial impact crater. Between a distance of about 25-35 feet, along the ground scar, there were three propeller slash marks in the soil. At a distance of 50 feet, along the ground scar, the right propeller hub assembly was found partially buried and about 5 feet further the left propeller hub assembly WA s found lying on the ground. A fan-shaped debris field originated from the completion of the ground scar. The debris field was centered on a northerly heading and measured 250 feet in length by 100 feet wide. The main wreckage was located at 40-degrees 11.278-minutes north latitude, 87-degreees 35.109-minutes west longitude. The main wreckage contained the empennage, tail surfaces, right engine nacelle, remnants of the main cabin, the carry-through wing spar, right and left main landing gear, and the left engine. The right engine was found 20 feet north of the main wreckage. Reconstruction of the main wreckage was conducted in a hangar at the Danville-Vermilion County Airport. Elevator and rudder control continuity was established from the control surfaces to the main cabin. Aileron control continuity was established from the aileron bellcranks to the main cabin. The main landing gear downlock assembly was in an orientation consistent with a retracted gear position. Left engine and valve train continuity was established by rotating the engine through the accessory section. Thumb compression was achieved on all cylinders and the upper spark plugs exhibited a light gray colo r with no oil fouling noted. The engine had been exposed to a post-impact fire and no fuel was noted in the fuel lines going to the fuel controller or in the spider-valve. The fuel screen was noted to be wet, clear of debris, and had the smell of fuel. Both left and right magnetos produced spark on all leads. The forward end of the crankshaft was broken in torsion from the flange. There was no debris found in the oil recovery pan and oil was present throughout the engine. The crankshaft, bearings, journals, and connecting rods were inspected and no anomalies were found. Right engine and valve train continuity could not be established due to impact damage on the forward gearing. The upper spark plugs exhibited a light gray color with no oil fouling noted. Fuel was found in the fuel line going to the fuel controller, fuel screen, and spider-valve. Both left and right magnetos produced spark on all leads. There was no debris found in the oil recovery pan and oil was present throughout the engine. The crankshaft, bearings, journals, and connecting rods were inspected and no anomalies were noted. Valve covers were removed and no anomalies were found with the valve train assem bly. The left propeller hub assembly and flange was sheared-off the crankshaft in torsion overload. The right propeller blades exhibited s-shape bending, leading edge gouges, and chordwise scratching on the propeller face and back surfaces. The right propeller hub assembly had pulled from the hub mounting bolts and part of the flange was fractured. The left propeller blades exhibited s-shape bending, leading edge gouges, and chordwise scratching the propeller face and back surfaces. One propeller tip had been broken in forward bending. One propeller blade was fractured into two parts at the blade root. (-23)N5038Q, a Cessna 310, took off on runway 21 at Danville, Illinois, at approximately 1909 local time with two people board. The aircraft was not on a filed flight plan with air traffic control. The weather conditions reported at Danville at 1932 local time were:winds, 180 degrees at 6 knots, 2.5 miles visibility with light rain and mist with a 1900 foot overcast. Witnesses stated that the aircraft took off on runway 21 and shortly thereafter a reduction in engine sound was heard. One witness stated that the airc raft appeared to descend briefly at this point and then began a climb into the clouds or haze. The witness lost sight of the aircraft at this time and didn't hear anything additionally. The aircraft impacted the ground approximately 1/2 mile southeast of the Danville airport on a northeasterly heading and both occupants sustained fatal injuries during the event.