[6] Flight 227, operated by a Boeing 727-22 departed LaGuardia Airport at 08:35 MST (10:35 EST) for San Francisco, California, with scheduled stops in Cleveland, Chicago, Denver, and Salt Lake City.

At 17:35, it was cleared to descend to 16,000 feet (4,900 m) by the Salt Lake City Air Route Traffic Control Center.

At 17:48, in response to the controller's request for the plane's altitude, the pilot replied "Okay we've slowed to two fifty (250 knots (460 km/h; 290 mph)) and we're at ten (10,000 feet (3,000 m)) we have the runway (34L) in sight now, we'll cancel and standby with your for traffic."

The captain indicated in post-crash interviews that at this point he moved the thrust levers to the takeoff power position, but the engines failed to respond properly.

The Boeing aircraft had been delivered to United seven months earlier in April, and had less than 1,800 hours of flight time.

[4] This accident was blamed entirely on the bad judgment of the captain, Gale C. Kehmeier, for conducting the final approach from a position that was too high and too close to the airport to permit a descent at the normal and safe rate.

When the plane crossed the outer marker, which marks the final approach segment, it was 2,000 feet (610 m) too high.

[4][7] The CAB (Civil Aeronautics Board) accident investigation revealed that the captain had a checkered training history.