Airport (less than 10 km from airport)

The accident is attributable to the fact that the crew wanted to make a landing with inadequate visual references from an unfavorable initial position and as a result, after touchdown the aircraft collided with a snowbank running along the runway.
The following factors contributed to the accident:
• The rapidly changing weather conditions on the mountain aerodrome of Samedan were misjudged by the crew.
• A coordinated crew working method in terms of crew resource manage-ment was missing.
• The deactivation of the EGPWS, which meant that acoustic messages con-cerning the aircraft’s height above ground and bank angle were no longer available in the final phase of the approach up to the first contact with the runway.
• A snowbank up to four metres high ran along the edge of the runway.

Engine failure for unknown reasons.

Findings as to Causes and Contributing Factors:
1. Contamination on the wings of the aircraft was not fully removed before take-off. It is likely that asymmetric contamination of the wings created a lift differential and a loss of lateral control.
2. Although the operator was not authorized for short take-off and landing (STOL) take-off on this aircraft, the crew conducted a STOL take-off, which reduced the aircraft’s safety margin relative to its stalling speed and minimum control speed.
3. As a result of the loss of lateral control, the slow STOL take-off speed, and the manipulation of the flaps, the aircraft did not remain airborne and veered right, colliding with obstacles beside the ski strip.
Findings as to Risk:
1. The out of phase task requirements regarding the engine vibration isolator assembly, as listed in the operator’s maintenance schedule approval, results in a less than thorough inspection requirement, increasing the likelihood of fatigue cracks remaining undetected.
2. The right engine inboard and top engine mounts had pre-existing fatigue cracks, increasing the risk of catastrophic failure.
Other Findings:
1. The cockpit voice recorder (CVR) contained audio of a previous flight and was not in operation during the occurrence flight. Minimum equipment list (MEL) procedures for logbook entries and placarding were not followed.
2. The Transwest Air Limited safety management system (SMS) did not identify deviations from standard operating procedures.

The student pilot failed to follow the checklist and set the takeoff trim properly prior to takeoff resulting in a loss of directional control. Contributing to the accident were the certified flight instructor's inadequate supervision and delayed remedial action.

The National Transportation Safety Board determines that the probable cause of this accident was the flight crew’s failure to monitor and maintain a minimum safe airspeed while executing an instrument approach in icing conditions, which resulted in an aerodynamic stall at low altitude.
Contributing to the accident were:
-the flight crew’s failure to follow published standard operating procedures in response to a flap anomaly,
-the captain’s decision to continue with the unstabilized approach
-the flight crew’s poor crew resource management,
-fatigue due to the time of day in which the accident occurred and a cumulative sleep debt which likely impaired the captain’s performance.

Failure of the right main gear upon landing for unknown reasons.

Findings as to Causes and Contributing Factors:
1. The crew conducted an Area Navigation (RNAV) approach for which they were not trained, with an aircraft that was not properly equipped nor approved for such purpose.
2. The aircraft descended 300 feet below the minimum descent altitude (MDA) as a result of a number of lapses, errors and adaptations which, when combined, resulted in the mismanaged approach.
3. The aural warning on the aircraft’s altitude alerter had been silenced prior to the approach, which precluded it from alerting the crew when the aircraft descended below minimum descent altitude.
4. The SkyNorth standard operating procedures for conducting a non-precision approach were not followed, which resulted in the aircraft descending below the minimum descent altitude. During the ensuing missed approach, the aircraft struck trees.
Findings as to Risk:
1. The lack of a more-structured training environment and the type of supervisory flying provided increased the risk that deviations from standard operating procedures (SOPs) would not be identified.
2. There are several instrument approach procedures in Canada that contain step-down fixes that are not displayed on global positioning system (GPS) units. This may increase the risk of collision with obstacles during step-downs on approaches.

The contrast between the area covered with snow and the snow-cleared area (the runway) induced the pilots visual sensation about the runway threshold. This caused the crew to miscalculate the touchdown point, causing the aircraft to land too far down the runway.