October 19, 19996, Flushing, New York, the airplane had struck the approach light structure and the end of the runway deck during the approach. Because of the captain's use of monovision contact lenses, he was unable to overcome the visual illusions resulting from the approach over water in limited light conditions (absence of visible ground features), the irregular spacing of the runway edge lights at shorter-than-usual intervals, the rain, and the fog, and that these illusions led the captain to perceive that the airplane was higher than it was during the visual portion of the approach, and thus, to his unnecessarily steepening the approach during the final 10 seconds before impact.

Aviation medical examiners (AMEs) need to know if pilot examinees are using contact lenses, and currently no process is in place to ensure that AMEs are provided with that information. The lag time in the display of vertical speed information in the vertical speed indicator installed in the accident airplane limited the first officer's ability to provide the captain with precise vertical speed information during the critical final seconds of the approach, and therefore contributed to the accident.

The probable cause was the inability of the captain, because of his use of monovision contact lenses, to overcome his misperception of the airplane's position relative to the runway during the visual portion of the approach. This misperception occurred because of visual illusions produced by the approach over water in limited light conditions, the absence of visible ground features, the rain and fog, and the irregular spacing of the runway lights. Contributing to the accident was the lack of instantaneous vertical speed information available to the pilot not flying, and the incomplete guidance available to optometrists, aviation medical examiners, and pilots regarding the prescription of unapproved monovision contact lenses for use by pilots.