United States of America

Following a Red Flag exercice from Tinker AFB, the aircraft was returning to Nellis AFB. Upon landing, the nose gear collapsed and the aircraft slid on the runway for few dozen metres before coming to rest, bursting into flames. All 32 occupants escaped uninjured while the aircraft was damaged beyond repair.

The pilot reported that he planned to fly a round trip cross-country flight. Prior to takeoff, he ascertained the quantity of fuel on board based upon the airplane's fuel totalizer gauge indication, which indicated 89 gallons. The flight to the destination was uneventful, and upon landing, 20 gallons of fuel was purchased. Thereafter, the pilot departed for the return flight back to his originating airport. According to the pilot, on takeoff the fuel tank gauges indicated the tanks were between 1/3 and 1/4 full. While cruising, the pilot contacted an air traffic control facility and notified them that he had lost power in one engine. About 5 minutes later, the pilot broadcasted that both engines were without power. Unable to reach the nearest airport, the pilot landed on soft, uneven terrain. During rollout, the airplane nosed over and was substantially damaged. The calculated post accident fuel burn-off for the round trip flight was about 106 gallons. During the post accident inspection, an FAA inspector reported finding an estimated 2 gallons of fuel in one tank. The other tank was dry. No fuel was observed in the main fuel lines to the engines, and no mechanical malfunctions were reported by the pilot.

The pilot purchased the airplane approximately one year prior to the accident with the intention of restoring it for flight. The airplane had not been flown for approximately five years and had been used for spare parts. The pilot was flying the airplane to another airport to pick up passengers prior to returning. The pilot was cleared for takeoff and to circle the airport at 2,500 feet prior to departing the area. Witnesses reported that after taking off the airplane seemed to “wobble” at a slow airspeed in a nose-high attitude and that it never got higher than 500 feet. Some witnesses reported the engine(s) sputtering, and another stated that the airplane was loud and "didn't sound good," although other witnesses reported that the engines sounded normal. One witness reported seeing white smoke coming from the left engine and hearing the engine "popping" as the airplane took off. The airplane made three left turns and it appeared as if the pilot was attempting to return to land. Witnesses described the left wing rising prior to the airplane banking hard to the left and the nose dropping straight down. The airplane impacted the ground just northeast of the airport property and a postimpact fire ensued. Flight control continuity was established. The right side of the elevator/tailcone structure exhibited black rub marks and scrapes. Grass and nesting material was found inside the left wing. The left fuel valve was found in the OFF position and the right fuel valve was positioned to the rear auxiliary tank. Neither the fuel crossfeed valve nor the fuel boost pump switch was located. The left engine sustained substantial fire and impact damage. The right engine sustained heavy impact damage. The airplane was last fueled one month prior to the accident with 120 gallons of fuel. About 20 engine test runs in addition to high-speed taxi tests had been conducted since then. A Special Flight Permit had been obtained but had not been signed by the mechanic, who did not know that the pilot was going to fly the airplane on the day of the accident. The pilot reportedly did not have any Beech 18 flight experience.

The private pilot/owner and a passenger were transporting the pilot's multi-engine airplane to another airport so it could undergo an annual inspection. Shortly after departure, the right engine began to vibrate violently and the pilot elected to make a forced landing to a pasture. The airplane caught on fire and both radial engines separated from the airframe and sustained impact damage. The pilot was not rated by the FAA to operate multi-engine airplanes and he had not received any formal training in the airplane. The accident flight was his first time flying the airplane by himself. The airplane had not received an annual inspection in approximately 8 years prior to the accident. Examination of the right engine revealed extensive mechanical damage possibly due to a connecting rod failure.

The airline transport pilot was on a Title 14, CFR Part 135 passenger flight. The pilot said during cruise flight he heard a loud bang, and the engine started running rough. He said he diverted to the nearest airport, but the engine quit completely, and he was unable to reach the runway. The airplane subsequently collided with terrain, sustaining substantial damage to both wings and the fuselage. An examination of the engine revealed that a locking screw had backed out of one of the anti-vibration counterweights on the crankshaft, scoring the interior back surface of the engine case. The unsecured counterweight then moved from its position in the crankshaft, and was likely struck by the engine's master rod, which shattered the weight, and liberated it from its normal location. The liberated counterweight was struck by internal moving parts, creating several component failures, and ultimately an engine seizure.

Prior to the accident flight, the pilot indicated that he was aware of the thunderstorm activity along his route of flight and that he anticipated deviating around the weather as necessary. While enroute to his destination, the pilot requested and was provided both weather information and pilot reports from other aircraft by air traffic control (ATC). Upon encountering an area of thunderstorm activity that extended east-to-west across the route of flight, the pilot reported encountering significant turbulence, and then downdrafts of 2,000 feet per minute. He then requested a course reversal to exit the weather before he declared an emergency and advised ATC that the airplane was upside down. There were no further transmissions from the pilot and radar contact with the airplane was lost. Review of radar data revealed that the pilot had deviated south and then southwest when the airplane entered a strong and intense echo of extreme intensity. Visible imaging revealed that the echo was located in an area of a rapidly developing cumulonimbus cloud with a defined overshooting top, indicating the storm was in the mature stage or at its maximum intensity. Two debris fields were later discovered near the area where the cumulonimbus cloud had been observed. This was indicative that the airplane had penetrated the main core of the cumulonimbus cloud, which resulted in an inflight breakup of the airplane. Near the heavier echoes the airplane's airborne weather radar may have been unable to provide an accurate representation of the radar echoes along the aircraft's flight path; therefore the final penetration of the intense portion of the storm was likely unintentional.

While in instrument meteorological conditions flying 800 feet above the airplane’s service ceiling (30,000 feet), with no icing conditions reported, the pilot reported to the air traffic controller that he, “...lost [his] panel.” With the autopilot most likely engaged, the airplane began a right roll about 36 seconds later. The airplane continued in a right roll that increased to 105 degrees, then rolled back to about 70 degrees, before the airplane entered a right descending turn. The airplane continued its descending turn until being lost from radar in the vicinity of the accident site. The airplane impacted in a nose-down attitude in an open field and was significantly fragmented. Postaccident inspection of the flight control system, engine, and propeller revealed no evidence of preimpact failure or malfunction. The flaps and landing gear were retracted and all trim settings were within the normal operating range. Additionally, the airplane was within weight and balance limitations for the flight. The cause of the pilot-reported panel failure could not be determined; however, the possibility of a total electrical failure was eliminated since the pilot maintained radio contact with the air traffic controller. Although the source of the instrumentation failure could not be determined, proper pilot corrective actions, identified in the pilot operating handbook, following the failure most likely would have restored flight information to the pilot’s electronic flight display. Additionally, a standby attitude gyro, compass, and the co-pilot’s electronic flight display units would be available for attitude reference information assuming they were operational.