Page:CAB Aircraft Accident Report, American Airlines Flight 2815.pdf/2

 the flight departed Detroit for Chicago with Cincinnati as the alternate. There is no evidence that the dispatcher urged Larsen to continue.

The flight proceeded to Chicago in continuous rain and was cleared to Surf intersection 12 miles east of Midway. The airport weather was reported at that time as ceiling 500 feet, visibility one mile. Runway 13, the instrument landing system runway, was then in use. Shortly thereafter, because of a change in wind direction, the active runway was changed to 31 and the flight was so advised. The ILS equipment for runway 31 differs from that for runway 13 in that runway 31 does not have a glide path or approach lights and the frequency of its localizer is 109.5 mcs. instead of 109.9 mcs.

Upon reaching the Surf intersection, the tower controller vectored the flight to the Kedzie fan marker, 3.3 miles from the active runway, and the final approach was started. During the approach the pilot reported to the tower that the localizer indicator in the aircraft was not functioning correctly. The controller then advised that the localizer frequency for runway 31 was 109.5 mcs. The captain changed from 109.9 mcs. to the proper frequency and the trouble was corrected. Captain Larsen explained later that he was using the wrong frequency because at that time he thought he was making a "back course" approach utilizing the runway 13 ILS. He said that the controller used the words "back course." This approach was discontinued at 600 feet above field elevation and the missed-approach procedure was started.

The first officer flew the airplane during a portion of the return to Kedzie while Captain Larsen studied the runway 31 IIS approach plate.

The landing gear was extended and the aircraft was trimmed for a rate of descent of 300 feet per minute. Both pilots stated that on this second attempt, according to their altimeters, they were never less than 100 feet above ground level and never more than two dots deflection from the centerline on the ILS indicator. Captain Larsen testified that there was turbulence during this second approach and that he was checking power and attitude instruments as well as looking over the glare shield while making a decision to go around or continue. Directly under and ahead of the aircraft approaching runway 31 was a large railroad yard with well-lighted areas, and a heavily traveled and brightly illuminated highway lay only a short distance to the left of course. Captain Larsen stated that he did not see this lighted area but suddenly saw a steel tower through a break in the clouds, attempted to pull up, applied power, and ordered the landing gear up.