Page:CAB Accident Report, United Airlines Flight 21.pdf/78

 would land on the east-west runway, but 40 seconds later changed his plan and stated that he would land on the northwest runway.

No sudden emergency occurred which made it necessary for Captain Scott to land on the northwest runway.

Under all the circumstances Captain Scott made an error of judgment in choosing the northwest runway for a landing.

Upon reaching a point approximately 700 feet southeast of the southeast corner of the airport at an altitude of approximately 160 feet, the airplane stalled, fell off to the left, and crashed while in an incipient spin.

Up to the instant before the crash the approach path was normal for a landing on the northwest runway, no structural or mechanical failure or malfunctioning of any part of the aircraft had occurred, and the aircraft was trimmed for a normal approach with gear down, flaps in the three-quarter position, and operating under approximately 25 percent horsepower.

Power was applied almost simultaneously with the stall, and no engine failure caused the stall or contributed to the crash.

Visibility from the cockpit was impaired during the approach due either to an accumulation of ice or mist on the windshield.

The aircraft had accumulated ice of a rough granular nature on the de-icer boots on the leading edges of the wings about ⅜ of an inch thick extending back for a distance of 2 inches on the top and bottom of the boots, and ice of a clear gaze type from 1/32 to 1/16 of an inch in thickness extending back on the boots almost to the attachment strip. Ice was also present on the de-icer boots on the tail surfaces.