Two pilots looking for the runway; no pilots watching airspeed
The day began for the crew when they arrived at KBA's Calgary International Airport (YYC) hangar at 0630 to prepare the King Air for the first leg to Edmonton City Centre Airport (YXD). They departed at 0845 with two passengers and arrived at YXD at 0936.
Eight passengers were boarded at Edmonton for the Kirby Lake leg. Prior to departure, the flight crew checked the weather conditions at Kirby Lake via an online service. They determined that conditions at Kirby Lake were not within the applicable limits to attempt the flight. The flight was delayed until 1016 when ceiling and visibility had improved. The King Air departed Edmonton at 1020.
Approximately 35 nm from Kirby Lake, the crew began to prepare for the RNAV instrument approach to Runway 08. Investigators said the crew engaged in a nonessential conversation — discussions not related to the operation of the aircraft — during the descent and approach to Kirby Lake. KBA 103 was cleared out of controlled airspace to conduct an instrument approach. Weather conditions near the time of the occurrence (1110) were: wind, 170 deg. T at 8 kt. gusting to 16 kt.; visibility, 4 sm in light snow, overcast ceiling at 600 ft. AGL; temperature, 3C, dew point, -4C.
The first officer was the pilot flying (PF) and flew an autopilot-coupled approach from the right seat. The GPS track information was only fed into the left-side HSI. So the first officer obtained lateral track information from the panel-mounted GPS unit in the center of the instrument panel.
This cross-panel view increased the instrument scan workload for the PF, said investigators. The flight proceeded toward the ROPRO waypoint (see accompanying approach plate) from the south with the intent of continuing to the DEDEK waypoint. During the descent, the crew began to encounter light to moderate icing conditions and elected to fly directly to the XIKIB waypoint on a track of 078 deg. M, bypassing the DEDEK waypoint and continuing the descent to 3,500 ft. ASL. Having deviated from the approach profile, the minimum sector altitude of 3,800 ft. ASL would have been applicable.
The approach profile was flown at 140 KIAS due to icing conditions. Anti-icing equipment was active and the deicing boots were activated six times during the approach. The flaps were set at the approach detent (12.9 deg.) and the crew confirmed that the RNAV 08 approach was loaded into the GPS unit and performed a RAIM check. They extended the landing gear and moved the propellers to fine pitch.
As KBA 103 approached the AXAXA final approach waypoint (4.9 nm from the threshold of Runway 08) the captain said he would be looking outside in order to locate the airport.
The approach procedure allows a descent to 2,760 ft. to the MDA after crossing AXAXA. The crew had agreed to round off the MDA to 2,700 ft. ASL. Neither crewmember made the required calls of 100 ft. prior to 2,700 ft. ASL or passing through and descending below 2,700 ft. ASL. (The outside surface temperature was -3C. A cold temperature correction was not applied to the altitudes on this approach; if it had been, the MDA would have been corrected to 2,796 ft. ASL — 536 ft. AGL.)
At approximately 4 nm from the threshold of Runway 08, the captain called the runway in sight; however, the first officer (PF) was not able to identify the runway. Throughout the remainder of the approach, both pilots were predominantly looking outside of the aircraft. The GPS course deviation indicator indicated that KBA 103 was slightly right of track. The PF disconnected the autopilot and proceeded to re-intercept the inbound track, flying the aircraft by hand.
Approximately 3 nm from the runway, the captain identified the road that led to the airport, indicating that the runway was to the left of the road. At about 1 mi. final, the captain pointed out the radio tower to the right of the runway (located midfield); however, the PF still did not have the runway in sight. Shortly thereafter, the PF identified the runway. Approximately 14 sec. later, the airplane's left wing dropped and the crew lost control of the aircraft. There was no audible warning to the approach of a stall. Maximum power was applied, but recovery was not achieved prior to the aircraft hitting the ground.
The left wing made initial contact and the fuselage impacted the ground in a tail-low attitude on a level, grass- and scrub-covered field that ended with a 17-ft. uphill slope to the runway threshold. The King Air bounced and ultimately came to rest on the left edge of the runway, facing the opposite direction. The total length of the wreckage trail was 439 ft.
The left wing and cockpit were substantially damaged. The cabin remained intact, although three seats broke free. Two passengers were able to evacuate via the emergency exit on the right-hand side. The remaining passengers evacuated through the main cabin door on the left side. The first officer was able to extract himself from his seat and was assisted from the aircraft by the passengers. The captain remained in the left seat until emergency medical services personnel were able to extricate him from the aircraft. Local personnel on the airport apron initiated an emergency response; emergency medical services personnel treated the injured occupants until they were transported to medical facilities. A small, post-impact, electrical fire ignited in the front, left-hand side of the cockpit area. Passengers and first responders used handheld fire extinguishers to put it out.
The investigation determined that the engines were producing high power at impact. Propeller blade marks on the ground indicated that the aircraft impacted the terrain at an approximate ground speed of 108 kt. Damage to the aircraft suggests that it experienced a low-energy impact.