The National Transportation Safety Board Wednesday marked the 40th anniversary of the crash of Air Florida flight 90 with a blog about the accident and how changes were made in its aftermath to improve aviation safety.

On Jan. 13, 1982, the Boeing 737 departed Washington National Airport in a snowstorm and crashed into the 14th Street Bridge. Of the 79 passengers and crew, 74 died in the accident and four more people on the bridge lost their lives.

The NTSB determined the probable cause was the flight crew's failure to use the engine anti-ice system, proceeding with the takeoff with snow and ice on the airfoil surfaces, and the captain's failure to reject the takeoff when there were anomalous engine instrument readings.

The blog was by written by Jeff Marcus, chief of the NTSB Safety Recommendations division, who was a DC-based employee with the National Highway Traffic Safety Administration at the time. Marcus recalls the details of the accident, the heroic efforts to save those who survived the initial impact with the bridge, and the progress that has been made to address airframe icing on commercial airliners.