NTSB Factual Report

On January 30, 2005, approximately 1135 Pacific standard time, the crew of a Southwest Airlines 737, N350SW, inadvertently aligned their aircraft for a landing on Taxiway Tango at Seattle-Tacoma International Airport, Seattle, Washington (SeaTac). There were no injuries to any of the crew members, nor to any of the 41 passengers, and the aircraft was not damaged. The 14 CFR Part 121 scheduled domestic passenger flight, which was operating in visual meteorological conditions at the time of the incident, departed Albuquerque International Airport, Albuquerque, New Mexico, at 0940 mountain standard time. The flight crew had filed and activated an IFR flight plan at the initiation of the flight, and they were on a visual approach final at the time of the event.

According to the First Officer, who was the flying flight crew member during the approach, as he rolled out on final after being vectored for a visual approach, he aligned the aircraft with the paved surface that he was convinced was Runway 16 Right, but was actually Taxiway Tango. He then continued the approach until the aircraft was about 500 feet above ground level (AGL), whereupon he noticed the large yellow "X" just off the north end of Taxiway Tango. At that point he realized that the surface that he intended to land on was not an operational runway, so he decided to initiate a go-around. At almost the same time as the First Officer realized he was aligned with the incorrect surface, the Captain came to the same conclusion, and directed the First Officer to execute a go-around. According to data retrieved from the Flight Data Recorder (FDR), the go-around was initiated at 250 feet AGL. After completing a successful go-around, the flight crew received vectors to a second visual approach final, whereupon they completed an uneventful full-stop landing. Although the FAA Control Tower had the Runway End Identifier Lights (REIL's) for both Runway 16 Left and Runway 16 Right on at the time of the first approach, both flight crew members stated that they had not seen the REIL's for either runway during this approach. When they came around for the second approach, the tower had turned on the sequencing approach flashers (rabbit) for Runway 16 Right, and according to the flight crew, it was at that time that they first saw the REIL's for either runway.

In further discussions with the flight crew, it was determined that although in the pre-approach briefing they had not specifically reviewed the notes and diagrams associated with the ongoing Taxiway Tango misidentification problems at SeaTac, they were both aware that other crews had inadvertently lined up on the taxiway in the past. It was further determined that although the First Officer had the localizer displayed on his navigational instruments, once he had identified the surface he was going to land on, he did not continue to monitor the displacement of the localizer needle. During the same interview, the Captain stated that he had the VOR set on his navigational instruments, and that a significant amount of his attention was directed toward looking for traffic around Boeing Field, handling radio communications, and monitoring the flight instruments. Both flight crew members said that although the paved surfaces where wet and a little shiny (from an earlier shower), they felt it was the shape, size, and color of the taxiway surface that most directly contributed to the misidentification.

This incident was the eighth in a series of known events wherein flight crews inadvertently aligned their aircraft with the subject taxiway with the intent to land on its surface. During three of these events the aircrews completed their landings on the taxiway surface. Although both airport operations personnel and the local FAA Airports Inspector were aware of this series of events, no markings or visual cues had been placed directly on the taxiway surface to assist crews in more easily identifying Taxiway Tango as a taxiway and not a runway.

This investigation has also determined that even though in June of 2004 the National Transportation Safety Board recommended the Federal Aviation Administration apply large-scale taxiway identification markings directly to the Taxiway Tango surface, in conjunction with applying a continuous serpentine centerline (Safety Recommendation A-04-48), as of the date of this report, no additional markings or visual cues of any sort have been added to the concrete surface of Taxiway Tango.

NTSB Probable Cause

The flight crew's failure to maintain an adequate visual lookout while on final for a visual approach. Factors include the failure of both airport operations personnel and the local FAA Airports Inspector to insure that some form of identification marking was placed directly on the taxiway surface after the first seven misalignment events.