What happened
While taxiing via a starter extension, the flight crew began a turn to line up on runway 0 09. Due to dark ambient conditions, the captain opted to turn the aircraft early to avoid the risk of exiting the pavement. During this maneuver, the crew performed required ready checks, which diverted their attention from monitoring the aircraft's position. Consequently, the aircraft drifted away from the taxi guidance line and positioned itself close to the right edge of the runway.
As the aircraft approached the runway, the captain mistook a row of white lights for centerline markings. This visual illusion, combined with the crew's belief that they were correctly aligned, led them to commence the take-off roll from a misaligned position. The resulting excursion caused damage to the aircraft and the runway edge lights. Following the incident, the crew performed a low pass of the Melbourne Airport ATC tower to visually inspect the landing gear, as they had no specific procedures for such an event and had not contacted their operator for guidance.
The investigation
Investigators examined the crew's focus and the environmental conditions at the time of the incident. The investigation found that the crew's attention was primarily absorbed by internal flight deck tasks during the turn. Furthermore, the presence of additional pavement on the starter extension likely provided erroneous visual cues, making the runway appear wider than it actually was. The investigation also noted that the crew's belief in their correct alignment was reinforced by confirmation bias, as they interpreted visible threshold and edge lights as evidence of proper positioning.
Findings
- The crew's attention was diverted by the performance of ready checks during the taxi maneuver, leading to a loss of situational awareness regarding the aircraft's position.
- The aircraft commenced the take-off roll from a misaligned position, resulting in physical damage.
- Visual illusions caused by dark conditions and non-standard pavement markings led the crew to misidentify the runway centerline.
- The crew's decision to perform a low pass for gear inspection was conducted without contacting the operator or following established procedures.
- An unprescribed medication was detected in the captain's post-incident testing, though no impairment was confirmed.