Page:Aviation Accident Report, American Export Airlines Flight 71.pdf/11

- 10 - The crash so completely demolished the aircraft that the flaps could not have been actuated in any manner whatsoever after the impact.

The possibility of a short circuit in this switch or in any other part of the electrical system which would in any manner operate the flap operating mechanism has been thoroughly explored but seems very remote.

The flap selector switch has six positions. The 20° position is located comparatively at 1:00 o'clock on the dial; the 10° position at 12:00 o'clock, "Flight" at 11:00 o'clock, "Raise" at 10:00 o'clock, "Off" at 9:00 o'clock; and.

The flap selector switch, as originally installed, was of somewhat different design than the one being used or the subject flight. On the former switch the "off" was located on a relative point of the clock dial at 9:00 o'clock; "10°" at 11:00 o'clock; "20°" at 1:00 o'clock, and "35°" at 3:00 o'clock. As a safety measure, this switch was redesigned and on June 3, 1942 the new switch was installed. This new design added a "flight" and a "raise" position, both of which operated the flaps to result in 0° setting. The "off" position then was to permit the stopping of the flaps at any point the operator desired from 0° to 35°. The 35° position was changed to 8:00 o'clock, which was below the "flight" and "raise" and "off", at the lowest position of the dial. In addition, a safety stop-spring arrangement was provided so that in order to put the switch on "raise", "off" or "35°", it was necessary for the operator to release the stop-spring. It appears from the testimony that this stop-spring had not been on the switch for sometime previous to the accident and it could not be ascertained whether it had been broken off or had been taken off. Furthermore, the captain and first officer testified that they had no recollection of there ever having been a stop-spring on the flap control