Accident
On the morning of the accident, United Trainer 16, a training flight operated by United Air Lines, departed Stapleton Airfield at 0655 local time. The aircraft was crewed by Senior First Officer Jordan D. Kocher, designated as captain and instructor, and trainee first officers Laurence G. Wilson and Wayne C. Moen. The flight was cleared for a training flight of four hours' duration within a 25-mile radius of Denver.
Flight and Load Details
Captain Kocher occupied the left pilot's seat at takeoff. The aircraft carried 820 gallons of gasoline, full oil tanks, and 650 pounds of sand ballast tied down in the rear baggage pit, in addition to the crew. The load was properly distributed with respect to the aircraft's center of gravity, and the takeoff gross weight of 22,910 pounds was within allowable limits. The aircraft was lightly loaded, carrying only the crew and fuel, oil, and ballast.
Weather Conditions
The crew had been briefed on weather conditions recorded at 0628: ceiling measured 15,000 feet, visibility 25 miles, and wind northwest at 14 knots. At the time of the accident, ceiling and visibility were unlimited, with wind northwest at 16 knots. No radio contacts were made by United Trainer 16 after reporting departure time.
Witness Observations
Witnesses reported that between 0720 and 0725, the aircraft was seen to stall, enter a spin, and strike the ground in a diving attitude before recovery could be effected. The aircraft stalled at an altitude of approximately 8,200 feet MSL (about 3,200 feet above the ground), entered a spin, and crashed before recovery.
Investigation
Examination of the wreckage revealed no evidence of malfunctioning or failure of the aircraft or its components. No malfunctioning was reported prior to the accident. Power was being developed by both engines upon impact.
Probable Cause
The Board found that the probable cause of this accident was an inadvertent spin at an altitude too low for recovery.