Page:NTSB Aircraft Accident Report, United Airlines Flight 389.pdf/36

 reveals no evidence of any irregularities or signs of unusual operation on the part of the crew. The record also indicates that there was no known or observed traffic that conflicted with UAL 389 during the period of its observation on radar inbound from the Pullman VORTAC. Additionally there were no components of another aircraft in the recovered wreckage nor were any aircraft reported missing in the accident area.

The flight's first descent clearance was issued at 2103 and called for an immediate descent through FL 310. Based on the shipboard witness testimony the impact measured to the last whole minute was at 2120. The pilot reported leaving 35,000 feet at 2103 and leaving 28,000 feet at 2108. At 2109 he reported leaving 26,000. At 2114.36 the SAGE computer reported track number A 039 to be at an altitude of approximately 16,500 feet, and finally at 2119.54 SAGE reported track K 047 to be at approximately 2,000 feet. At the time this latter altitude was recorded the flight was holding a clearance which limited its descent to 6,000 feet. Furthermore, the crew was in radio contact with the approach controller at this time in routine radio transmissions relating to their approach to the Chicago area. Included in this last transmission was a reference to the latest altimeter setting. Track K 047 is assessed as being associated with UAL 389 because there was no other known or observed radar traffic in the area where the track appeared plus its correlation with track A 039 which in turn can be associated with UAL 389 by comparison of the ARTCC controller's recollection of the flight path and positions of UAL 389 over known fixes. Again there was no other known or observed high altitude traffic that could have appeared in the computer as this track except UAL 389.