North Dakota

The commercial pilot was conducting a cross-country, business flight with 10 passengers onboard the 8-passenger airplane. He reported that air traffic control cleared the flight for an instrument landing system (ILS) approach to the runway. While descending, the airplane entered instrument meteorological conditions (IMC) at 3,100 ft mean sea level (msl), and ice started to accumulate on the wing's leading edges, empennage, and windshield. The pilot activated the pneumatic deice boots multiple times during the approach and slowed the airplane to 120 knots. The airplane then exited the clouds about 400 ft above ground level (agl), and the pilot maintained 120 knots as the airplane flew over the airport fence; all indications for landing were normal. About 100 ft agl, the airplane started to pull right. He applied left correction inputs, but the airplane continued to pull right. He applied engine power to conduct a goaround, but the airplane landed in grass right of the runway, sustaining damage to the wings and landing gear. Witnesses and passengers reported that the airplane stalled. During examination of the airplane immediately after the accident, about 1/2 to 1 inch of mixed ice was found on the right wing's leading edge, the vertical and horizontal stabilizers, and the angle of attack probe. Ice was also observed on the windshield. The flaps were found in the "up" position. Flight control continuity was established. Although the airplane was originally certificated for two-pilot operation, the pilot was flying the airplane under a single-pilot exemption. The pilot received a logbook endorsement indicating that he had received single-pilot training and was properly qualified under the single-pilot exemption. However, he
had not met the turbine flight time qualifications (1,000 hours) to be properly authorized to conduct the flight under the single-pilot exemption because he only had 500 hours. A review of cockpit voice recorder information indicated that, although the pilot verbalized that the landing gear was "all green," followed by stating "check, check, check," he did not verbalize all the approach or landing checklist items nor did he make any audible comments about activating the pneumatic deice boots or windshield anti-ice. A review of radar data for the flight indicated that, during the last 2 minutes of flight, while the airplane was on final approach to the runway, the indicated airspeed got as low as 99 knots. The last recorded radar return indicated that the airplane had an airspeed of 104 knots at 900 ft msl. The pilot's lack of minimum flight experience required to fly the airplane without a copilot likely led to task saturation as he flew the airplane entered IMC and icing conditions while on an ILS approach. He subsequently failed to lower the flaps during the approach, which resulted in a no-flap approach instead of a full-flap landing. The ice on the leading edges of the wings, the no-flap approach, and the low airspeed likely led to the exceedance of the airplane's critical angle of attack, which resulted in an aerodynamic stall.

The pilot and two medical crewmembers were repositioning the airplane to pick up a patient for aeromedical transport. Dark night instrument meteorological conditions prevailed for the flight. Radar data showed the airplane climb to 14,000 ft mean sea level after departure and proceed direct toward the destination airport before beginning a right descending turn. The airplane subsequently broke up inflight and impacted terrain. No distress calls were received from the pilot before the accident. Although weather conditions were conducive for inflight icing, no evidence of structural icing was identified at the scene. The debris field was 2,500 ft long and the disbursement of the wreckage confirmed that both wings, the horizontal stabilizer, both elevators, and both engines separated from the airplane before impacting the ground. Examination of the wreckage revealed that the initiating failure was the failure of the wing where it passed through the center of the airplane. The three wing spars exhibited S-bending deformation, indicative of positive overload producing compressive buckling and fracture. Further, impact signatures as black paint transfers and gouged aluminum, were consistent with the left outboard wing separating when it was struck by the right engine after the wing spars failed. There was no evidence of any pre-exiting conditions that would have degraded the strength of the airplane structure at the fracture locations. Flight control continuity was confirmed. An examination of the engines, propellers, and available systems showed no mechanical malfunctions or failure that could have contributed to the accident. The descending right turn was inconsistent with the intended flight track and ATC-provided clearance. However, there was insufficient information to determine how it was initiated and when the pilot became aware of the airplane's state in the dark night IMC conditions. Yet, the
absence of a distress call or communication with ATC about the airplane's deviation suggests that the pilot was not initially aware of the change in state. The structural failure signatures on the airplane were indicative of the wings failing in positive overload, which was consistent with the pilot initiating a pullup maneuver that exceeded the airplane spars' structural integrity during an attempted recovery from the spiral dive.

The airplane was equipped with an air sampling system used to collect air samples at various altitudes. The accident occurred when the pilot was returning to the airport after taking air samples at various altitudes over oil fields. As he was being vectored for an instrument approach, the airplane overshot the runway's extended centerline. The pilot then reported that he had a fire on board. The airplane lost altitude rapidly, and radar contact was lost. Examination of the accident site indicated that the airplane struck the ground at high velocity and a low impact angle. One piece of the airplane's shattered Plexiglas windshield exhibited soot streaking on its exterior surface. This soot streaking did not extend onto the piece's fracture surface, indicative of the smoke source being upstream of the windshield and the smoke exposure occurring before windshield breakup at impact. Both nose baggage compartment doors were found about 2 miles south of the main wreckage, which indicative that they came off at nearly the same time and most likely before the pilot's distress call. Although there was no soot deposits, thermal damage, or deformation to the doors consistent with a "high energy explosion," the separation of the luggage compartment doors could have occurred due to an overpressure caused by the ignition of a fuel air mixture within the nose portion of the airplane. The ignition of fuel air mixtures can create overpressure events when they occur in confinement. An overpressure in the nose baggage compartment may have stretched the airframe enough to allow the doors to push open without deforming the latches. If it was a lean fuel air mixture, it would likely leave no soot residue. Post-accident examination revealed no evidence that the air sampling system, which was strapped to the seat tracks behind the copilot's seat, was the cause of the fire. The combustion heater, which was mounted in the right front section of the nose baggage compartment, bore no evidence of fuel leakage, but a fuel fitting was found loose.

The airplane was substantially damaged when it impacted an open field about 1-1/2 miles south of the destination airport. The pilot had executed an instrument approach and was circling to land when the accident occurred. Night instrument meteorological conditions prevailed at the time. The area south and east of the airport was sparsely populated. The pilot reported that he obtained the Automated Weather Observing System (AWOS) broadcast for the destination via the aircraft radio while en route. He stated the reported visibility was above that required for the Non-Directional Beacon (NDB) approach, however, the ceiling was below the minimum descent altitude (MDA). He reported that he attempted to contact air traffic control (ATC) with the intention of diverting. He was not able to contact ATC and elected to continue to the destination. The pilot reported that he flew the entire NDB approach and stated: "When I arrived at the MDA, I saw the runway, directly below and a little to my left. My plan, at the time, was to circle left and land." He stated after that point he had no further recollection of the events surrounding the accident. The pilot reported that there were no failures or malfunctions associated with the aircraft. Two witnesses reported seeing lights from an airplane near the airport. One recalled that the weather was "foggy and a heavy mist." The other witness stated: "When I saw the plane it was very low but I thought it was going around for the landing because it looked like the plane had its right wing higher, and I could see part of the belly of the plane, which made it look like it was banking around." Flight control continuity was confirmed during a post-accident examination. The airport AWOS recorded an overcast sky at 400 feet above ground level (agl). The MDA for the instrument approach as 694 feet above field elevation.

The airplane was making an instrument landing system approach in instrument meteorological icing conditions when control was lost. The airplane impacted the terrain 1.6 miles from the approach end on the runway. The airplane contacted the terrain with the left wing first prior to cartwheeling and coming to rest approximately 120 feet from the point of first impact. The pilot had 19 hours total flight time in Cessna 208's of which 1.9 hours were in actual instrument meteorological conditions.

After deplaning passengers at Thief River Falls after an air taxi flight, the pilot was reportedly anxious to return to his base in Minot to prepare for another trip the following day, and left for the return trip within a few minutes after his arrival at Thief River Falls. There was no record of a weather briefing. Observations of Doppler radar by the University of North Dakota, and a Safety Board meteorological study, show that the airplane had penetrated a thunderstorm when control was lost. The airplane had encountered the center of a microburst, and was located directly under the downdraft.

The airplane was cruising at 6,000 feet where it encountered icing conditions. When cleared to 3,600 feet, the pilot reported that one engine lost all power and the other one was running rough. The airplane continued the descent. After about ten minutes the airplane departed controlled flight, reversing heading and impacting near vertically in the terrain. A post accident examination of the left engine (which was feathered) found an induction duct which had deteriorated and begun to come apart. Foreign object material in the compressor assembly similar in appearance to material from the duct was found. The number five piston had a hole burned through it.

The public use flight was being operated by the Indian Health Service of the U.S. Department of Health & Human Services. It departed VFR from Devils Lake, North Dakota, with an intended destination of Rolla, North Dakota. The pilot attempted two visual approaches at Rolla, but encountered whiteout conditions due to a snow storm. He obtained an IFR clearance and diverted to Minot. He flew two ILS approaches to runway 31 at Minot and reported a missed approach after each. Radio contact was lost after the second approach. About an hour later, a snow plow operator found wreckage on the airport. Investigation revealed the plane had impacted to the right of runway 31 with the gear retracted and the flaps extended 15°. The 0959 weather was in part: 600 feet obscured, visibility 1/2 mile variable in snow, wind 110° at 11 knots. No preimpact mechanical anomaly was found with the airplane or engines. All four occupants were killed.

Shortly after a night takeoff from Jamestown Airport, the twin engine airplane encountered difficulties to gain height when it struck power cables and crashed in a field located in Spiritwood, about eight miles from the airport. The aircraft was destroyed and the pilot, sole on board, was killed.

The crew was completing a crop spraying mission against grasshoppers in the region of Sheridan. While flying at a relative low altitude, the crew made a 45° turn when the airplane stalled, spiraled and crashed in flames. Both occupants were killed.