Quoted from Party Submissions
There you have some answers! One of the last 4 files
INTERNATIONAL BROTHERHOOD OF TEAMSTERS Submission:
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1. Autopilot Does Not Disconnect
Discussions with Boeing’s Air Safety Investigation team revealed that the autopilot system is designed such that control column input force that overrides a single channel autopilot servo on the 767-300 will not result in autopilot disconnect, but rather an illumination of the autopilot caution light. A review of the Boeing 767 manual reveals no notes or cautions to this effect. However, in the simulator training environment the built-in protections of simulator control loading will disconnect the autopilot and release the control columns when excessive force is applied during a maneuver or malfunction of the simulator control loading.
The IBT investigators believe this difference has the potential for a ‘negative learning’ transfer from the simulator training environment to actual line flying. While it did not appear to have a direct impact on the accident, the Boeing 767 manuals should be corrected to highlight this system architecture difference for all operators.
2. EFI Switch and Symbol Generator Malfunction
Investigators have been unable to determine the exact failure scenario that required the rapid transfer of controls back and forth between the First Officer and the Captain. Based on a review of the CVR, it appears there may have been a right symbol generator failure of the First Officer’s EFIS59 screens. Selecting the EFI switch to ALTN60 mode would have sourced the center symbol generators. Since this EFI switching event occurred so close to the final upset event, it is possible that the First Officer may have mistrusted his EFIS screen readings and relied instead on sensory input as to aircraft attitude. This EFI/symbol generator event should not have affected the round-dial (analog) airspeed indicators on either pilot’s instrument panel or the backup ISFD in the center left panel for airspeed/attitude crosschecking purposes.
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EDIT: And read their recommendations.