The Northwestern Air BAe Jetstream 3112 (registration C-FNAY) was operating as flight PLR734 on an instrument flight rules (IFR) flight from Hay River Airport, NT (YHY) to Fort Smith Airport, NT (YSM). After conducting an IFR approach to runway 11, PLR 734 executed a missed approach and flew a full procedure approach for runway 29. At approximately 0.2 nautical miles from the threshold, the crew sighted the approach strobe lights and continued for a landing. Prior to touchdown, the aircraft entered an aerodynamic stall and landed hard on the runway. The aircraft remained on the runway despite the left main landing gear collapsing. The two flight crew members and three passengers were uninjured and evacuated the aircraft through the left main cabin door. There was no post-impact fire. FINDINGS AS TO CAUSES AND CONTRIBUTING FACTORS: 1. Though icing conditions were encountered, the airframe de-icing boots were not cycled nor was the Vref speed increased to offset the effects of aircraft icing. 2. An abrupt change in aircraft configuration, which included a reduction in power to flight idle and the addition of 35§ flap, caused the aircraft’s speed to rapidly decrease. 3. The aircraft entered an aerodynamic stall due to the decreased performance caused by the icing. There was insufficient altitude to recover the aircraft prior to impact with the runway.