Page:CAB Aircraft Accident Report, American Airlines Flight 2815.pdf/4

 replacements because of reported malfunctionings for a six-month period of American's Convairs, DC-6's, and DC-7's disclosed no pattern of consistent trouble. Investigation showed that American's Douglas and Convair aircraft have altimeter static systems that have proved to be satisfactory through years of operation and are regarded by American as virtually trouble-free.

Investigation disclosed that the reporting of the Midway weather to the flight was both accurate and current. Thunderstorm conditions prevailed in the general area and lightning flashes could be seen in the northwest and northeast quadrants. Nevertheless, there was no frontal passage at the time and place of the accident which could have caused wind changes of sufficient magnitude to have significant effect upon the approach path.

A scheduled flight of Delta Airlines, also a Convair, landed at Midway, using runway 31, about three minutes before this accident. Its captain stated that he missed his first approach and was vectored back over the Kedzie fan marker and into position for his successful approach. During neither approach did he experience any appreciable drift or turbulence. The weather conditions he encountered were substantially as reported to him, and all ground radio navigational facilities functioned properly.

Captain Larsen had not been flying regularly into Chicago. His last previous landing there had been about three weeks before this accident and the preceding one had been six months earlier. He and First Officer Kinne had flown together only once, some 16 months earlier. The captain testified that he was familiar with the Chicago area but had not studied the Chicago approach plate recently nor prior to the Detroit-Midway leg of the flight.

Analysis

According to the approved approach procedure for an ILS/ADF approach to runway 31, the Kedzie fan marker should be crossed at an altitude of 900 feet above airport level, a gradual descent begun, and the descent continued until reaching minimum altitude at or near the middle marker six-tenths of a mile from the approach end of the runway. Upon reaching the middle marker or shortly thereafter, if the pilot does not have at least ceiling and visibility minimums, and the lights identifiable with the runway are not in sight, a missed-approach procedure must be started. The evidence clearly indicates that this procedure was not followed.

The captain's inability to execute the first approach properly stems from his failure to study the approach plate and his lack of knowledge of the procedure, even the frequencies involved. As he had studied the approach plate between the first and second approach, it is apparent that he must have been aware of the proper procedure during the second approach. A descent to a dangerously low altitude must have been made early in the second approach. Several facts point to this belief. The tower struck was only 96 feet high. It was located more than a mile from the approach end of the runway and it was 3,000 feet to the left of course. At impact the aircraft was in the approach configuration with respect to propeller governors and propeller blade pitch angles, and wing flaps with landing gear down and locked. It is evident that during the approach both the ILS and ADF pointers clearly indicated that the aircraft was off course to the left. In fact, the ILS pointer must have been fully deflected quite some time before impact. Since Captain Larsen was a well qualified instrument pilot