History of the Flight
Air Canada Jazz flight JZA447, a Bombardier CL-600-2D15 (registration C-FDJZ), departed Vancouver International Airport at 1129 Pacific Standard Time on a scheduled instrument flight rules (IFR) flight to Whitehorse, Yukon, with 54 passengers and 4 crew members. The first officer was designated as the pilot flying (PF), and the captain was the pilot not flying (PNF). The departure and en route segments were uneventful.
At 1246, control was transferred from Vancouver Area Control Centre (ACC) to Edmonton ACC North High Specialty, Klondike sector. The aircraft was at flight level 360. Radar service was terminated, and the flight was instructed to contact Edmonton ACC.
Approach and Communication
The aircraft was cleared for an approach to Whitehorse International Airport, which is located in a mountainous, non-radar environment. A winter snow storm was moving through the area at the time. The captain hand-flew the instrument landing system approach to Runway 31L using the head-up guidance system (HGS).
Whitehorse tower requested JZA447 to report 10 miles final and advised that sweeping was in progress. The crew acknowledged but did not provide a position report at 10 miles final, and no landing clearance was issued. The aircraft landed approximately nine minutes later, at 1350 Pacific Standard Time, after flying over two runway snow sweepers operating on the portion of the runway located before the displaced threshold for Runway 31L.
Events Leading to the Landing
Before the approach, JZA447 was held due to traffic. At 1339, the flight was cleared to the airport for an approach. The first officer contacted Whitehorse tower at 1341, reporting the approach clearance. The relieving tower controller (who had come on duty at 1339:35) provided runway information and instructed the flight to report at 10 miles out, confirming sweeping in progress. The first officer acknowledged. There was no further communication until the aircraft was on the runway.
At approximately 300 feet above runway elevation, the flight crew established visual contact with the runway and observed two sweeper trucks near the beginning of the displaced threshold area. The first officer advised the captain about the trucks and that no landing clearance had been received. Neither pilot observed vehicles in or beyond the normal touchdown zone, and no go-around was initiated. The captain, knowing the flight had been cleared for approach, believed the trucks were holding and continued the landing.
Aftermath
The threshold for Runway 31L was displaced 1400 feet. The two trucks (Truck 81 and Truck 84) were towing snow sweepers and had finished sweeping Runway 13R. Truck 81 turned around in the displaced threshold turn area, and Truck 84 was beginning to turn when the driver observed the aircraft on very short final. The aircraft's altitude over the beginning of the runway surface was calculated to be 126 feet above ground, and it cleared the trucks by about 110 feet before landing in the normal touchdown zone, approximately 2400 feet past the trucks.
The weather report issued 10 minutes after landing indicated a ceiling of vertical visibility 600 feet, visibility of 3/4 statute mile in light snow and drifting snow, and a runway visual range of 4500 feet.