History of Flight
On 25 October 2010, a Kenn Borek Air Ltd. Beechcraft 100 (registration C-FAFD, serial number B-42) operated as KBA103 on an instrument flight rules flight from Edmonton City Centre Airport to Kirby Lake, Alberta. The aircraft departed Calgary International Airport earlier that morning with two passengers, arriving at Edmonton at 0936. Eight additional passengers boarded for the leg to Kirby Lake. The flight was delayed due to weather conditions but departed Edmonton at 1020.
Approximately 35 nautical miles from Kirby Lake, the crew prepared for the RNAV (GNSS) approach to Runway 08. The first officer, as pilot flying, flew an autopilot-coupled approach from the right seat. Lateral track information for the pilot flying came from a panel-mounted GPS unit, increasing instrument scan workload. During descent, the crew encountered light to moderate icing and elected to bypass the DEDEK waypoint, continuing directly to XIKIB on a track of 078° Magnetic at 140 knots indicated airspeed. Anti-icing equipment was active and de-icing boots were activated six times.
As the aircraft approached the AXAXA final approach waypoint, the captain (pilot not flying) began looking outside to locate the aerodrome. After crossing AXAXA, the crew descended to the minimum descent altitude (MDA) of 2700 feet asl (rounded down from 2760 feet). Neither crew member made the required altitude callouts. At approximately 4 nm from the runway threshold, the captain visually identified the runway, but the first officer did not. Both pilots focused outside, and the aircraft deviated slightly right of track. The autopilot was disconnected, and the aircraft was hand-flown back to the inbound track. At about 1 nm final, both pilots had the runway in sight, but approximately 14 seconds later, the left wing dropped and control was lost. Maximum power was applied but recovery was not achieved, and the aircraft struck the ground 174 feet short of the runway threshold. The aircraft bounced and came to rest off the runway edge. The captain sustained fatal injuries; the co-pilot and three others sustained serious injuries; five passengers received minor injuries. A small electrical fire in the cockpit was extinguished by survivors and first responders.
Analysis
The Transportation Safety Board's investigation focused on crew performance. During the initial approach, the crew engaged in non-operational conversation, suggesting a lack of heightened attention. Critical items were missed, including descending below the minimum sector altitude while diverting and failing to announce reaching the MDA. After the captain identified the runway at 4 nm, both pilots primarily looked outside, neglecting to monitor airspeed and altitude. The aircraft continued descending and the airspeed decreased to the point of an aerodynamic stall. The aircraft was too low to recover despite attempts.
The stall warning system did not activate for unknown reasons, which may have provided an earlier alert. The investigation found that the use of company standard weights and a non-current weight and balance report resulted in an inaccurate takeoff weight, potentially affecting performance. Additionally, flying the approach using a navigational display outside the normal scan increased workload, and the abbreviated approach profile without proper transition altitudes increased risk.
Probable Cause
The conduct of the flight crew during the instrument approach prevented them from effectively monitoring the aircraft's performance. During the descent below the minimum descent altitude, the airspeed reduced to a point where the aircraft experienced an aerodynamic stall and loss of control, with insufficient altitude to recover. For unknown reasons, the stall warning horn did not activate.