Page:NTSB Aircraft Accident Report, United Airlines Flight 389.pdf/8

 information obtained by SAGE, two height finder readings were obtained.

The first, at 0214.6Z (2114:36) indicated the target was at 16,500 feet m.s.l. The second, at 0219.9Z (2119:54) indicated the target was at an altitude of 2,000 feet m.s.l. This latter altitude was considered by the Air Defense Command to be accurate within outside limits of +500 or -1,000 feet (1,000-2,500 feet m.s.l.). During the time of this latter altitude reading the aircraft was in voice communication with approach control and had an altitude clearance limit of 6,000 feet m.s.l.

Several witnesses on ships and along the western shore of Lake Michigan observed a ball of fire near the surface of the lake. These witnesses placed the time of their observation at 2120. Other witnesses reported the same general sightings but the time of their observations varied from 2100 to after 2130.

The accident location was determined by plotting the center of the wreckage distribution pattern and determined to be at a point 29.6 statute miles east-northeast of O'Hare Airport in 250 feet of water. The surface of the water is approximately 576.8 feet m.s.l. The coordinates were 87°27' 56" West - 42°15' 2" North.

1.2