Fargo-Hector

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 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 single engine airplane departed Fargo-Hector Field on a weather mission over Minnesota. While cruising at night at an altitude of 15,000 feet, the airplane entered an uncontrolled descent and crashed in an open field located some 5 km north of Moorhead. The aircraft was destroyed and both occupants were killed.