What happened
On 23 January 2020, a Bombardier CL600 2C10 (CRJ700), registration F-GRZL, was performing a commercial passenger flight from Lille to Lyon-Saint-Exupéry. The approach was conducted under Low Visibility Procedures (LVP) due to freezing fog, with visibility between 140 m and 300 m.
As the aircraft descended through 500 ft and entered the cloud layer, the pilot flying (PF) began following guidance cues from the Head-Up Display (HUD). During this phase, the PF executed several left roll inputs, causing the aircraft to deviate from the runway centerline. Simultaneously, the pilot monitoring (PM) was distracted by a radio reception issue involving his headset jack.
As the deviation increased, the PF applied a nose-up input that lasted approximately 33 seconds, causing the aircraft to climb above the glide path. The aircraft's airspeed dropped to 120 kt, which was 15 kt below the reference speed. The crew eventually initiated a missed approach by engaging the TOGA mode. During the climb, the aircraft flew over airport buildings and a taxiway at a low altitude, including proximity to the control tower, before the crew stabilized the flight and performed a second, successful approach.
The investigation
The BEA examined data from the Quick Access Recorder (QAR), radio communications, and radar. The investigation focused on why the aircraft deviated from the localizer and why the crew failed to detect the deviation earlier. Investigators analyzed the Head-up Guidance System (HGS) to determine which operating mode was active. While the aircraft was capable of CAT IIIa, the investigation found that the AIII mode was likely not active, meaning the crew lacked critical visual aids like the "Approach warning" and runway edge lines. The investigation also reviewed the crew's recent experience and the impact of the HUD on pilot attention.
Findings
- The aircraft was likely operating in a mode other than AIII, which deprived the crew of essential automated warnings and visual runway references.
- The pilot flying focused excessively on aligning HUD symbols (cognitive tunneling) rather than monitoring the localizer deviation.
- The pilot monitoring was not fully monitoring the primary flight displays due to a distraction with headset equipment.
- The missed approach was executed in a slow, non-standard manner, contributing to a loss of altitude and airspeed.
- The crew failed to verify that the correct approach mode was active during their standard pre-descent checks.