Because the way that autopilots works, it suddenly shifts the attitude of the aircraft (pulls the nose rapidly up or down).
Depending on speed, this can induce alot of G' forces, which can be seen as momentary blackouts/redouts.
And when you pull alot of G's, you are exceeding the G rating of the wings of the B-17, and snapping them off.
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WB's: (verm--), **MOL**, Men of Leisure,
"Real men fly Radials, Nancy Boys fly Spitfires
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