Page:CAB Accident Report, American Airlines Flight 1.pdf/19

 stalled. In any event, it seems clear that immediately after levelling out, and perhaps executing a slight climb, the airplane dived to the ground. If the airplane was stalled, the subsequent dive to the ground might well have been the beginning of a spin which was prevented from developing completely into a spin only by the proximity of the ground.

The possibility that some difficulty might have developed in the fuel system as a result of turning the fuel selector valve, in the vicinity of the point at which the airplane descended, for the purpose of using gasoline from a different tank, has been considered. Assuming that the flight had been operating on the left auxiliary tank after take-off from Buffalo, it appears that the gasoline supply of that tank would have decreased to approximately 10 gallons when the flight arrived at a point perhaps 5 to 8 miles east of the scene of the accident, at which time, according to the testimony of one of American's officials, it would have been normal procedure to change to another tank. If such change were not made, the left auxiliary tank probably would have become empty approximately at the point where the descent was begun.

A preponderance of evidence, however, indicates that both engines were operating until the airplane struck the ground. Although three witnesses believed that only one engine was operating, most of the witnesses believed that the sound which they heard was that of two engines. Moreover, the conditions observed during the examination of the wreckage at the scene of the accident and during the subsequent disassembly and inspection of the engines and propellers support the probability that both engines were operating normally.

The fact that the airplane descended with considerable speed in an abnormal attitude, without landing lights on and with flaps up, indicated that a landing was not being attempted. There were several nearby landing areas known to Captain Cooper for which he could have headed had he wished to land. The fact that the ignition switch was found in the "on" position tends to indicate either that the captain and first officer were making every effort to the very end to keep the airplane in flight or that they were unable, as a result of incapacitation, to cut the switch.

A lack of radio communication immediately prior to the time of the accident indicates either that the radio ceased to function or that trouble developed so suddenly and so violently that there was no time to use the radio. However, the fact that all of American's stations concerned with the flight, even Chicago, had been receiving messages from Flight 1 without difficulty indicated that the radio transmitter had been functioning normally.

The singular flight path and attitudes of the airplane immediately preceding the impact, especially in view of the apparent spiral character of the maneuvers described, would seem to lead most naturally and reasonably to the conclusion that a failure or jamming of some element or elements of the control system occurred. The behavior of the airplane during the descent strongly indicates that it was under partial control at the time and suggests a situation in which the pilot might have been unable completely to straighten out the flight path because of a failure of some particular control to respond in the normal manner to his manipulations. As previously stated, however, a thorough examination of all control elements found in the wreckage not only failed to reveal any evidence of breakage, jamming or other malfunctioning during flight, but on the contrary, gave considerable indication that all such control elements had been in satisfactory working condition until the airplane struck the ground. It appears probable, therefore that if any failure of the control system occurred it was in some portion which was completely destroyed by fire and the condition of which it was impossible to determine. Whether any such failure occurred, and, if so, what particular element was affected necessarily remains within the realm of speculation.