What happened
On a scheduled instrument flight from Edmonton to Peace River, the crew of an Air Canada Regional de Havilland DHC-8-100, registration C-FDND, experienced a landing error due to visual confusion. During a VOR/DME approach to Runway 22, the crew identified what they believed to be the runway threshold. However, at 0906, the aircraft touched down in a snow-covered, grassy area located 151 feet to the right of the actual runway and 1900 feet beyond the threshold.
The flight service station specialist observed the off-runway touchdown and instructed a go-around. The crew successfully transitioned back to flight after traveling 1300 feet along the ground. Following the incident, a 20-foot swath of the runway was cleared of snow to improve visibility. The crew attempted a second approach but aborted the landing after failing to establish a stabilized approach. The aircraft eventually returned to Edmonton without further incident. There were no injuries and no damage to the aircraft.
The investigation
The investigation focused on why the crew experienced perceptual confusion. It was determined that the grassy area shared a similar rectangular shape, orientation, and color profile to the intended runway. The presence of brown grass protruding through the snow, combined with tire tracks in the grass, mimicked the appearance of a sand-treated runway.
Investigators also examined the runway maintenance procedures. The airport maintainer had not swept the runway prior to the arrival, partly due to concerns that sweeping might reduce friction, and a lack of awareness regarding the need to maintain visual contrast between the runway and the surrounding terrain. Furthermore, the absence of specialized lighting, such as RILS or ODALS, meant there were no significant visual cues to alert the crew to their lateral displacement.
Findings
- The crew fell victim to perceptual confusion because the snow-covered grass area closely resembled the intended runway in shape and location.
- The airport maintainer did not provide visual contrast between the runway and the field because they were unaware of the requirement to do so.
- The maintainer's decision not to sweep the runway was influenced by a concern that sweeping might make the surface more slippery.
- The lack of specific runway lighting systems, such as RILS or ODALS, prevented the crew from detecting they were off-course.
- The runway environment was obscured by snow, which blended the active runway with the adjacent terrain.
Safety action
Following the occurrence, Air Canada Regional issued a Flight Operations Bulletin to its pilots. This bulletin addressed the risks of visual illusions and introduced a new procedure requiring pilots to ensure runway lighting systems are operational and to consider using maximum intensity during low-visibility or snow-covered conditions.