What happened
On January 6, 2007, a Korean Air Lines Boeing 737-900, registration HL7724, was operating a scheduled flight from Incheon International Airport to Akita Airport. During the final approach to Runway 10, the aircraft mistakenly descended onto a parallel taxiway located on the south side of the runway.
The flight was conducting a VOR/DME No.1 approach under instrument flight rules. At the time of the incident, the weather was characterized by moderate rain and strong crosswinds. As the aircraft descended, the crew engaged in a discussion regarding the visual identification of the runway, noting that the Precision Approach Path Indicator (PAPI) appeared to be positioned far to the left. Despite the confusion, the pilot in command disengaged the autopilot and continued the landing. Upon touchdown, the crew realized they had landed on a taxiway rather than the intended runway. There were no injuries among the 133 people on board, and the aircraft sustained no damage.
The investigation
The Japan Transport Safety Board (JTSB) examined the flight data from the Digital Flight Data Recorder (DFDR) and the Cockpit Voice Recorder (CVR). The investigation focused on the cockpit communications, the functionality of the Head Up Display (HUD), and the meteorological conditions at the time of the approach. Investigators also reviewed the approach charts for the VOR/DME No.1 RWY 10 procedure and the specific alignment of the approach course relative to the taxiway.
Findings
The primary cause of the incident was the flight crew's misidentification of the parallel taxiway as the active runway. Several contributing factors were identified:
- The crew failed to reconfirm the relative positions of the runway and the taxiway during the approach.
- Poor visibility caused by moderate rain and the use of windshield wipers made visual identification difficult.
- The crew lacked specific knowledge that the VOR No.1 approach course runs parallel to the runway direction.
- The pilot in command operated under the mistaken belief that the Flight Director Guidance Cue (FDGC) on the HUD was indicating the correct runway centerline.
- The approach course (105°) was identical to the runway heading, and the extended line of the approach path led directly toward the taxiway.
Safety action
Following the investigation, Korean Air Lines modified its airway manual to include a specific caution for pilots using the VOR/DME No.1 RWY 10 approach, warning them of the risk of confusing the runway with the taxiway. Additionally, recommendations were made to improve the clarity of approach charts and to reinforce the responsibilities of air traffic controllers in intervening during abnormal approach conditions.