From accident to improvement
The light on the aisle floor is only one example of safety features that have become obligatory in all airliners as a result of a crash.
1971: PLANE HITS MOUNTAIN SIDE IN DENSE FOG
Accident: At an altitude of 750 m, a Boeing 727 approaching the Juneau Airport in Alaska strikes a mountain side and is destroyed. Because of dense fog and clouds, the pilots weren't able to see anything. Result: All major planes are equipped with the Ground Proximity Warning system. Objects that rise above the flying altitude are marked in red on a display.
1983: LAVATORY FIRE HAS FATAL CONSEQUENCES
Accident: During a flight from Dallas, Texas, to Toronto, Canada, a Douglas DC-9 must force-land due to fire. The smoke makes it difficult for passengers to find the emergency exits, and 23 people die. Result: The floors of all airliners include shining stripes that guide passengers to the emergency exits in the dark. Smoke alarms become mandatory in lavatories.
1985: FLEEING PASSENGERS TRAPPED BY EMERGENCY EXIT
Accident: A Boeing 737 abandons take-off in Manchester Airport due to fire, immediately landing again. During the evacuation, an emergency exit "traffic jam" makes 55 people die of smoke inhalation. Result: At the emergency exits above the wings, seats are removed to allow more space for evacuation, and standard evacuation procedures are introduced.