No aircraft commander would ever have put a B-17 into a steep dive as Col. Gallagher. The aircraft was not built or stressed for maneuvers like that and the excess G forces on pull out would have destroyed the aircraft.
Angel Babe's tail markings continually change throughout the episode. When she taxis in at the 2:00 minute mark it is triangle A. When the tire blows on takeoff at 12:00 it has changed to triangle P. When she takes off for the mission is has changed back to triangle A but when she lands from the same mission at 32:00 there are no tail markings. When Joe takes it for a test flight at 32:00 it changes to square A. During the final mission at 40:00 it has changed back to triangle A but the serial number has changed from 3703 to 23814. She was truly a magical plane.
Colonel Gallagher puts "Angel Babe" into a dive to avoid flak. However, the stock footage used to show the dive is simply that of a B-17 in level flight which has been tilted as an angle. The clouds in the background are also at the same angle.
When Gallagher puts the Angel Babe into a steep dive, the scene cuts to the waist gunners hanging on to keep from sliding into the bulkhead of the plane. However the scene shows them oriented as if the plane is in a steep bank (side to side) rather than a steep dive (front to back)
After engine 3 loses oil and no longer operates, scenes show Angel Babe flying the mission with all four engines functioning.