Cessna 421C Golden Eagle III

The pilot was conducting a personal cross-country flight with one passenger in his twin-engine airplane. There was no record that the pilot received a weather briefing before the accident flight. While en route to the destination, the pilot was in contact with air traffic control and received visual flight rules flightfollowing services. About 18 miles from the destination airport, the radar service was terminated, as is typical in this geographic region due to insufficient radio and radar coverage below 7,000 ft. The airplane was heading northeast at 4,900 ft mean sea level (msl) (about 2,200 ft above ground level [agl]). About 4 minutes later, radar coverage resumed, and the airplane was 6 miles west of the airport at 4,100 ft msl (1,400 ft agl) and climbing to the north. The airplane climbed through 6,000 ft msl (3,300 ft agl), then began a shallow left turn and climbed to 6,600 ft msl (3,800 ft agl), then began to descend while continuing the shallow left turn ; the last radar data point showed the airplane was about 20 nm northwest of the airport, 5,100 ft msl (2,350 ft agl) on a southwest heading. The final recorded data was about 13 miles northwest of the accident site. A witness near the destination airport heard the pilot on the radio. He reported that the pilot asked about the cloud height and the witness responded that the clouds were 800 to 1,000 ft agl. In his final radio call, the pilot told the witness, "Ok, see you in a little bit." The witness did not see the airplane in the air. The airplane impacted terrain in a slightly nose-low and wings-level attitude with no evidence of forward movement, and a postimpact fire destroyed a majority of the wreckage. The damage to the airplane was consistent with a relatively flat spin to the left at the time of impact. A postaccident examination did not reveal any preimpact mechanical malfunctions or anomalies that would have precluded normal operation. A detailed examination of the cockpit instruments and other portions of the wreckage was not possible due to the fire damage. A cold front had advanced from the northeast and instrument meteorological conditions prevailed across the region surrounding the accident site and the destination airport; the cloud ceilings were 400 ft to 900 ft above ground level. The airplane likely experienced wind shear below 3,000 ft, and there was likely icing in the clouds. While moderate icing conditions were forecast for the accident site, about the time of the accident, investigators were unable to determine the amount and severity of icing the flight may have experienced. The weather conditions had deteriorated over the previous 1 to 2 hours. The conditions at the destination airport had been clear about 2 hours before accident, and visual flight rules conditions about 1 hour before accident, when the pilot departed. Based on the available evidence it is likely that the pilot was unable to maintain control of the airplane, which resulted in an aerodynamic stall and spin into terrain.

After takeoff, the commercial pilot saw flames coming from the left engine nacelle area. He retarded the throttle and turned off the fuel boost pump; however, the fire continued. He then feathered the propeller, shut down the engine, and maneuvered the airplane below the clouds to remain in the local traffic pattern. He attempted to keep the runway environment in sight while drifting in and out of clouds. He was unable to align the airplane for landing on the departure runway, so he attempted to land on another runway. When he realized that the airspeed was decreasing and that the airplane would not reach the runway, he landed it on an adjacent grass field. After touchdown, the landing gear separated, and the airplane came to a stop. The airframe sustained substantial damage to the wings and lower fuselage. Examination of the left engine revealed evidence of a fuel leak where the fuel mixture control shaft inserted into the fuel injector body, which likely resulted in fuel leaking onto the hot turbocharger in flight and the in-flight fire. A review of recent maintenance records did not reveal any entries regarding maintenance or repair of the fuel injection system. The pilot reported clouds as low as 500 ft with rain, snow, and reduced visibility at the time of the accident, which likely reduced his ability to see the runway and maneuver the airplane to land on it.

The commercial pilot of the multi-engine airplane was conducting an instrument flight rules cross-country flight at night. The pilot checked in with air traffic control at a cruise altitude about 10,000 ft mean sea level (msl). About 31 minutes later, the pilot reported that he saw lightning off the airplane's left wing. The controller advised the pilot that the weather appeared to be about 35 to 40 miles away and that the airplane should be well clear of it. The pilot responded to the controller that he had onboard weather radar and agreed that they would fly clear of the weather. There were no further communications from the pilot. About 4 minutes later, radar information showed the airplane at 10,400 ft msl. About 1 minute later, radar showed the airplane in a descending right turn at 9,400 ft. Radar contact was lost shortly thereafter. The distribution of the wreckage, which was scattered in an area with about a 1/4-mile radius, was consistent with an in-flight breakup. The left horizontal stabilizer and significant portions of both left and right elevators and their respective trim tabs were not found. Of the available components for examination, no pre-impact airframe structural anomalies were found. Examination of the engines and turbochargers did not reveal any pre-impact anomalies. Examination of the propellers showed evidence of rotation at impact and no pre-impact anomalies. Review of weather information indicated that no convection or thunderstorms were coincident with or near the airplane's route of flight, and the nearest convective activity was located about 25 miles west of the accident site. Autopsy and toxicology testing revealed no evidence of pilot impairment or incapacitation. Given the lack of radar information after the airplane passed through 9,400 ft, it is likely that it entered a rapid descent during which it exceeded its design stress limitations, which resulted in the in-flight breakup; however, based on the available information, the event that precipitated the descent and loss of control could not be determined.

While conducting a post maintenance test flight in visual flight rules conditions, the private pilot of the multi-engine airplane reported an oil leak to air traffic control. The controller provided vectors for the pilot to enter a right base leg for a landing to the south at the nearest airport, about 7 miles away. The pilot turned toward the airport but indicated that he did not have the airport in sight. Further, while maneuvering toward the airport, the pilot reported that the engine was "dead," and he still did not see the airport. The final radar data point recorded the airplane's position about 3.5 miles west-northwest of the approach end of the runway; the wreckage site was located about 4 miles northeast of the runway, indicating that the pilot flew past the airport rather than turning onto a final approach for landing. The reason that the pilot did not see the runway during the approach to the alternate airport, given that the airplane was operating in visual conditions and the controller was issuing guidance information, could not be determined. Regardless, the pilot did not execute a precautionary landing in a timely manner and lost control of the airplane. Examination of the airplane's left engine revealed that the No. 2 connecting rod was broken. The connecting rod bearings exhibited signs of heat distress and discoloration consistent with a lack of lubrication. The engine's oil pump was intact, and the gears were wet with oil. Based on the available evidence, the engine failure was the result of oil starvation; however, examination could not identify the reason for the starvation.

According to the line service technician who worked for the fixed-base operator (FBO), before taking off for the air ambulance flight with two medical crewmembers and one patient onboard, the pilot verbally asked him to add 40 gallons of fuel to the airplane, but the pilot did not specify the type of fuel. The line service technician drove a fuel truck to the front of the airplane and added 20 gallons of fuel to each of the multiengine airplane's wing tanks. The pilot was present during the refueling and helped the line service technician replace both fuel caps. Shortly after takeoff, a medical crewmember called the company medical dispatcher and reported that they were returning to the airport because smoke was coming from the right engine. Two witnesses reported seeing smoke from the airplane Several other witnesses reported seeing or hearing the impact and then immediately seeing smoke or flames. On-scene evidence showed the airplane was generally eastbound and upright when it impacted terrain. A postimpact fire immediately ensued and consumed most of the airplane. Investigators who arrived at the scene the day following the accident reported clearly detecting the smell of jet fuel. The airplane, which was equipped with two reciprocating engines, should have been serviced with aviation gasoline, and this was noted on labels near the fuel filler ports, which stated "AVGAS ONLY." However, a postaccident review of refueling records, statements from the line service technician, and the on-scene smell of jet fuel are consistent with the airplane having been misfueled with Jet A fuel instead of the required 100LL aviation gasoline, which can result in detonation in the engine and the subsequent loss of engine power. Postaccident examination of the engines revealed internal damage and evidence of detonation. It was the joint responsibility of the line technician and pilot to ensure that the airplane was filled with aviation fuel instead of jet fuel and their failure to do so led to the detonation in the engine and the subsequent loss of power during initial climb.In accordance with voluntary industry standards, the FBO's jet fuel truck should have been equipped with an oversized fuel nozzle; instead, it was equipped with a smaller diameter nozzle, which allowed the nozzle to be inserted into the smaller fuel filler ports on airplanes that used aviation gasoline. The FBO's use of a small nozzle allowed it to be inserted in the accident airplane's filler port and for jet fuel to be inadvertently added to the airplane.