What happened
On December 25, 2005, a WestJet Airlines Boeing 737-700, registration C-GWJF, was completing a scheduled passenger flight from Toronto to Halifax. During the final stages of the approach to Runway 14 in darkness and low visibility, the aircraft's flight path became unstable. At approximately 67 feet above the ground, the pilot flying disconnected the autopilot. This manual transition was accompanied by an unintentional 30-degree right roll and a slight pitch up.
As the aircraft descended, the pilot flying inadvertently activated the take-off/go-around (TOGA) mode instead of the auto-throttle disconnect. The resulting maneuvers caused the aircraft to deviate from the runway centerline. The aircraft touched down firmly on the left main gear with a 16-degree left bank, causing the left wing to strike the runway surface. While there were no injuries to the 132 passengers or 6 crew members, the aircraft sustained damage to the left wing tip, flap components, and tail cone.
The investigation
The investigation focused on the crew's approach procedures and the information provided prior to landing. It was established that the crew had originally planned for a Category II approach to Runway 23 based on ACARS and ATIS reports. However, because the RVR reports provided by dispatch did not specify the applicable runway, the crew mistakenly believed visibility was sufficient for Runway 20. Upon descending, the crew learned that Runway 23 was below landing limits, forcing an unplanned transition to a Category I approach for Runway 14. This required rapid reprogramming of the flight management system and a new approach briefing.
Investigators also examined the cockpit environment, noting that the crew did not utilize the company's required monitored approach procedure. Furthermore, the investigation was hindered by the fact that the cockpit voice recorder (CVR) was not deactivated after the incident, causing critical data from the moments following the wing strike to be overwritten.
Findings
- The crew failed to perform a pilot monitored approach, which removed a vital safety layer designed to manage low-visibility transitions.
- The transition to manual flight became destabilized due to the unintentional disconnection of the autopilot and the subsequent activation of the TOGA mode.
- The pilot flying's actions were influenced by limited experience on the aircraft type and the high-stress environment of the low-visibility landing.
- The captain did not take command or initiate a go-around once the aircraft's path became unstable.
- The touchdown point and delayed use of reverse thrust significantly increased the risk of a runway overrun.