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off about 4 minutes before landing. He thought that the absence of windshield ice resulted from cockpit heat and the windshield de-icer blower.
He proceeded to the scene of the accident immediately after the crash and inspected the ice on the fin antenna of United 21, which he described as 1-½ inches in diameter and similar to the ice on the fin antenna of his own ship. The policeman present at the scene of the accident did not allow him to examine any other part of the ship.
Captain Herman Carson piloted American Airlines Trip 15 from Detroit and landed at Chicago at 6:07, shortly after the crash. He checked over the range station at 8000 feet and reported rime ice, which was effectively disposed of by the de-icer boot, from that altitude down to 5000 feet. From 5000 feet until he broke out of the overcast at 1300 feet, a fair amount of clear ice was picked up which caused a sloppiness of the controls and instability of the ship and covered the windshield. As the plane entered the overcast, the indicated air speed fell off about 20 miles per hour without any change of the control setting. Preparatory to landing, Captain Carson increased his manifold pressure to 36 inches and reported an indicated air speed of 120 to 125 miles per hour, at which speed his manifold pressure under normal conditions would be about 25 inches. He came over the airport boundary at a speed of 115 miles an hour and dove onto the runway in a steep glide. He estimated that his actual landing speed was about 110 miles an hour, and that the ship stalled at this speed just above the ground. He was in the icing condition for 25 minutes and although part of the windshield was covered with ice about an inch thick, the hot air blower de-icer maintained an opening sufficient for visibility in landing. Although the tower gave him the option of landing either west or northwest with the wind reported as north
