What happened
On 24 February 2023, a Korean Air Boeing 787-9, registration HL-7209, was taxiing at Singapore Changi Airport for a scheduled departure from Runway 02R. During the taxi sequence, the aircraft entered a section of Taxiway T that had been temporarily closed for signage maintenance. As the aircraft proceeded, its nose landing gear struck a red and white striped marker board used to demarcate the closed area. The impact caused the board to break and left scuff marks on the aircraft's tires. The aircraft eventually came to a stop approximately 100 meters past the damaged board. There were no injuries to the 273 people on board, and no significant damage was sustained by the aircraft beyond the tire scuffs.
The investigation
The investigation focused on why the crew failed to follow the assigned taxi route and why the closed section was not identified. Investigators found that the crew had reviewed the relevant Notices to Airmen (NOTAMs) but had misread the expiration time of the closure notice, mistakenly believing the closure ended at 09:00 local time instead of 09:00 UTC. This error led the crew to expect a direct route that did not account for the restricted area.
Furthermore, the investigation examined the crew's response to Air Traffic Control (ATC) instructions. While the Pilot Monitoring (PM) correctly read back the instruction to use Taxiways P3 and P1, the crew failed to execute the turn onto Taxiway P3. The investigation also looked into the visibility of the marker board, noting that while it was discernible from a distance, the Pilot Flying (PF) perceived the red and white stripes as mere ground markings rather than a warning of a closed area.
Findings
- The crew's misinterpretation of the NOTAM expiration time caused them to be unaware that the taxiway closure was still in effect.
- A lack of familiarity with the specific taxiway layout led the PM to search for Taxiway P1 in the wrong orientation, as they expected it to be perpendicular to Taxiway T when it is actually parallel.
- The PF's preconceived expectation of a straightforward route created a cognitive bias, causing them to dismiss the red and white marker board as a standard ground marking.
- Crew Resource Management (CRM) was suboptimal, as the PF did not seek clarification regarding the unusual markings, and the PM did not alert the PF to the difficulty in locating the assigned taxiway.
Safety action
Following the incident, the aircraft operator implemented several safety measures, including issuing a fleet-wide notice and adding the event to the agenda for safety meetings. The involved crew members were enrolled in CRM training focusing on communication and situational awareness, and the incident has been integrated into the operator's advanced airmanship courses.