Page:Aviation Accident Report, United Air Lines Flight 4.pdf/11

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properly during the approach of the trip.^[1]

Under United's standard instrument procedure for trips approaching Salt Lake City, the north leg of the Salt Lake Radio Range and the south leg of the Ogden Radio Range, which overlie each other, are used. As a supplement to the monitoring of these legs which is accomplished by personnel and instruments on the ground, the approach procedure includes provision for a check, by the pilot, of the alignment of each of the two legs. On trips approaching from the west, the pilot tunes the aural long wave receiver to the Ogden range while approaching the Salt Lake Range Station in order to check the alignment of the south leg of the Ogden Range. If that leg bears on the Salt Lake Range Station, the procedure into Salt Lake is started, using the south leg of the Ogden Range northbound as far the Layton Marker. Constant back bearings are taken with the ADF^[2] tuned to the Salt Lake Range. At the Layton marker the alignment of the south leg of the Ogden Range is compared with that of the north leg of the Salt Lake Range. If legs coincide, a procedure is made and the low approach into Salt Lake is completed with both the long wave receiver and the ADF tuned to the Salt Lake Range.

↑ In addition to the usual monitoring conducted by outlying stations, the north leg of the Salt Lake Radio Range is monitored by a receiver located a short distance north of the station. An Esterline Angus Recorder continuously records the operation of the leg. Moreover, Equipment affording means of visual and aural monitoring is located in the Communications Station of the Civil Aeronautics Administration and the dispatch offices of United and Western Air Lines. Whenever an instrument approach is being made on the north leg, one person in each of these offices is assigned the duty of continuously monitoring the operation of the leg and reporting any deviation to the pilot immediately. All of these facilities indicated that the north leg was in proper position during the approach of Trip 4.
↑ The ADF, or Automatic Direction Finder, is a radio device which, through the use of a needle indicator, points continuously in the direction of the radio station to which it is tuned.

[1] In addition to the usual monitoring conducted by outlying stations, the north leg of the Salt Lake Radio Range is monitored by a receiver located a short distance north of the station. An Esterline Angus Recorder continuously records the operation of the leg. Moreover, Equipment affording means of visual and aural monitoring is located in the Communications Station of the Civil Aeronautics Administration and the dispatch offices of United and Western Air Lines. Whenever an instrument approach is being made on the north leg, one person in each of these offices is assigned the duty of continuously monitoring the operation of the leg and reporting any deviation to the pilot immediately. All of these facilities indicated that the north leg was in proper position during the approach of Trip 4.

[2] The ADF, or Automatic Direction Finder, is a radio device which, through the use of a needle indicator, points continuously in the direction of the radio station to which it is tuned.

[1]

[2]