Delta Air Lines Flight 554: Undershot Landing


The undershot landing occurred at LaGuardia Airport, New York, on 19 October 1996 (NTSB, 1997[2]). During the landing on runway 13, the Delta Air Lines McDonnell Douglas MD-88 aircraft struck the approach light system and runway deck structures (Dismukes, 2007[1]). Due to the great impact, the main landing gear separated from the aircraft body, leading to the sliding of the aircraft down the runway on its fuselage belly (Dismukes, 2007[1]). As a result, the lower fuselage was substantially damaged and three passengers injured (NTSB, 1997[2]).

Main Cause

Captain’s Use of the Monovision Contact Lenses1
The use of monovision lenses led to misconception of the distance between the aircraft and the runway during approaching (NTSB, 1997[2]). Normally, in the form of binocular vision, the brain fuses the two images from two eyes into a single three-dimensional image, aiding in the depth perception2 (NTSB, 1997[2]). However, when using monovision contact lenses, the brain would be unable to fuse the disparate images, causing degraded depth perception (NTSB, 1997[2]). Therefore, the use of monovision lenses along with the special design of the runway and the environmental conditions gave the captain a wrong perception that the runway was more distant and the aircraft was higher than it was, thus, he descended steeply before the impact, leading to the accident (NTSB, 1997[2]).

Remedial Actions

1. The optometric associations should inform all the optometrists that the pilots’ use of monovision contact lenses was prohibited and encourage them to advise pilot-rated patients of the related hazards of wearing monovision contact lenses (NTSB, 1997[2]).
2. Delta Air Lines should take the responsibility to inform all pilots about the prohibition of the use of monovision contact lenses through internal guidance (NTSB, 1997[2]).

1. Dismukes, R. K., Berman, B. A. and Loukopoulos, L. D. (2007). The Limits of Expertise: Rethinking Pilot Error and the Causes of Airline Accidents. England: Ashgate Publishing Limited.
2. National Transportation Safety Board. (1997). Aircraft Accident Report: Descent below Visual Glidepath and Collision with Terrain, Delta Air Lines Flight 554, McDonnell Douglas MD-88, N914DL Laguardia Airport, New York, October 19, 1996. Washington DC: The Board.
3. Civil Aviation Authority. (1998). Aviation Medicine Manual. England:Westward Digital Limited.

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