What happened
The aircraft was approaching the airport from the east under winter conditions. Approximately two inches of snow had fallen the previous night. Snow removal equipment had cleared Runway 26L, Runway 26R, and Taxiway Charlie. However, all runways and taxiways remained covered with up to one-eighth of an inch of melting slush, leaving approximately 60-75% of the surface obscured.
The flight crew was cleared to land on Runway 26R. At the time, Runway 26L was being used for instrument approaches. The airport layout featured four parallel concrete-covered strips. From left to right, these were Runway 26L, Taxiway Charlie, Runway 26R, and Runway 25. Notably, Runway 26L and Taxiway Charlie were the same length.
The crew reported seeing what appeared to be three snow-plowed runways ahead: Runway 26L, Runway 26R, and Runway 25. In reality, the middle strip they identified as a runway was Taxiway Charlie. The taxiway had a load-bearing weight capacity of only 700,000 pounds. The crew landed on this middle strip.
Critical lighting conditions contributed to the confusion. All runway lights, taxiway lights, and associated approach lighting had been turned off, with the exception of the Runway 26R VASI lights. During the final approach, the crew agreed they were lined up with Runway 26R but noted that the glare was "real bad."
The investigation
The investigation focused on the visual cues available to the flight crew during the final approach. Investigators examined the snow removal records and the status of airport lighting systems. It was determined that the slush coverage obscured surface markings, making it difficult to distinguish between runways and taxiways without proper lighting.
Findings
The primary factor in this incident was the misidentification of the landing surface. The crew confused Taxiway Charlie with a runway due to the lack of visible lighting and the presence of snow plowing on adjacent surfaces. The absence of runway and taxiway edge lights, combined with glare from the slush-covered concrete, prevented the crew from correctly identifying their alignment.
The airport's configuration of parallel strips of equal length exacerbated the issue. Without clear visual differentiation provided by lighting or distinct surface markings, the crew selected the wrong strip for landing. The load-bearing capacity of the taxiway was insufficient for the aircraft, posing a significant risk of structural damage.
Safety message
This incident highlights the critical importance of airport lighting during winter operations. When runways and taxiways are covered in snow or slush, reliance on visual cues alone is hazardous. Airports must ensure that adequate lighting is operational to distinguish between active runways and taxiways, especially when surface markings are obscured by weather conditions.