Cessna 208B Grand Caravan

Findings as to Causes and Contributing Factors:
1. The engine lost power when a compressor turbine blade failed as a result of the overstress extension of a fatigue-generated crack. The fracture initiated at a metallurgical anomaly in the parent blade material and progressed, eventually resulting in blade failure due to overstress rupture.
2. The combination of aircraft position at the time of the engine failure, the lack of equipment enabling the pilot to locate and identify high terrain, and the resultant manoeuvring required to avoid entering instrument flight conditions likely prevented the pilot from attempting to glide to the nearest airfield.
Findings as to Risk:
1. Single-engine instrument flight rules (SEIFR) operations in designated mountainous regions have unique obstacle risks in the event of an engine failure. Canadian equipment requirements for such operations do not currently include independent terrain mapping, such as terrain awareness and warning systems (TAWS).
2. Airline operators are not currently required to conduct any additional route evaluation or structuring to ensure that the risk of an off-field landing is minimized during SEIFR operations.
3. Pilots involved in commercial SEIFR operations do not receive training in how to conduct a forced landing under instrument flight conditions; such training would likely improve a pilotís ability to respond to an engine failure when operating in instrument meteorological conditions (IMC).
4. Mean time between failure (MTBF) calculations do not take into account In Flight Shut Downs (IFSDs) not directly attributable to the engine itself; it may be more appropriate to monitor all IFSD events.
5. The design of the Cessna 208B Caravan fuel shutoff valves increases the risk that the valves will open on impact, allowing fuel spillage and increasing the potential for fire.
Other Finding:
1. Sonicblue Airways was not providing downloaded engine parameter data for engine condition trend monitoring (ECTM) evaluation at appropriate intervals.

A partial loss of engine power for an undetermined reason during the initial takeoff climb resulting in an in-flight collision with objects.

Loss of control in icing conditions.

The loss of engine power due to the failure of the engine-driven fuel pump. A contributing factor was the inadequate inspection of the engine driven fuel pump.

Findings as to Causes and Contributing Factors:
1. The aircraft departed at a weight exceeding the maximum take-off weight and the maximum weight for operation in icing conditions.
2. After departure from Winnipeg, the aircraft encountered in-flight icing conditions in which the aircraftís performance deteriorated until the aircraft was unable to maintain altitude.
3. During the attempt to return to the Winnipeg International Airport, the pilot lost control of the aircraft, likely with little or no warning, at an altitude from which recovery was not possible.
Findings as to Risk:
1. Aviation weather forecasts incorporate generic icing forecasts that may not accurately predict the effects of icing conditions on particular aircraft. As a result, specific aircraft types may experience more significant detrimental effects from icing than forecasts indicate.
2. Bulk loading prevented determining the cargo weight in each zone, resulting in a risk that the individual zone weight limits could have been exceeded.
3. The aircraftís centre of gravity (CG) could not be accurately determined, and may have been in the extrapolated shaded warning area on the CG limit chart. Although it was determined that the CG was likely forward of the maximum allowable aft CG, bulk loading increased the risk that the CG could have exceeded the maximum allowable aft CG.
4. The incorrect tare weight on the Toronto cargo container presented a risk that other aircraft carrying cargo from that container could have been inadvertently overloaded.
Other Findings:
1. The pilotís weather information package was incomplete and had to be updated by a telephone briefing.
2. The operatorís pilots were not pressured to avoid using aircraft de-icing facilities or to depart with aircraft unserviceabilities.
3. The aircraft departed Winnipeg without significant contamination of its critical surfaces.
4. The biological material on board the aircraft was disposed of after the accident, with no indication that any of the material had been released into the ground or the atmosphere.
5. The fact that the aircraft was not equipped with flight data recorder or cockpit voice recorder equipment limited the information available for the occurrence investigation and the scope of the investigation.

The fatigue failure of the compressor turbine stator vane, the liberation of vane material into the compressor turbine, and the total loss of engine power. Also causal was the operator's failure to inspect the compressor turbine vane during fuel nozzle checks.

Loss of control on landing for unknown reasons. It was not possible to determine whether the heavy rainfall that occurred in the region effectively contributed to the loss of control of the aircraft on the ground. In addition to the narrowing of the runway, the position of the drainage ditch became an obstacle, which prevented the aircraft from decelerating safely, culminating in the collision of the front landing gear against it and the impact of the propeller on the ground.

Loss of control during initial climb due to windshear after weather conditions suddenly changed as a thunderstorm was approaching the airport.