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one mile with a light drizzle, light fog and light smoke, the temperature was 33 degrees, dewpoint temperature 31 degrees, and the wind was west northwest 9 miles per hour. This observation also contained a pilot's report that the top of the overcast was 5,000 feet with light to moderate ice between 1,000 and 5,000 feet. At 5:02, Trip 21 reported over the McCool fan marker at 6,000 feet, flying in and out of the base of the upper overcast. At 5:09, Trip 21 was cleared from Lansing to the Chicago range station at 6,000 feet on the northwest leg. A special weather report from Chicago, issued at 5:10, was transmitted to Captain Scott at 5:15 from which it appeared that the ceiling was 600 feet with lower broken clouds, visibility three-quarters of a mile, with light snow, light fog and light smoke, the temperature 32 degrees, the dewpoint 31 degrees, and the wind west northwest 9 miles per hour.
At 5:22, United 21 reported over the Chicago range. At 5:24 Airway Traffic Control advised that United 21 was in No. 3 position to land and gave United's Chicago dispatcher the following message for Captain Scott.[1]
"And here's something for him now. Tell him that the ship before him picked up an inch and half of the ice down at four and three thousand feet. Tell him I think personally that he would do better to hold 6,000 until he is No. 1 approach. * * * * he can come down now as far as 4,000 feet if he wishes but I would prefer to have him stay at 6 account of the ice."
- ↑ When an aircraft arrives over an airport under instrument conditions and there is other traffic also operating in that area preparing to land at the airport, Airway Traffic Contral assigns each aircraft an approach number. They are then permitted to land as quickly as is consistent with safety and, unless an emergency exists, no landing priority is given to any aircraft.
