Page:CAB Accident Report, Pennsylvania Central Airlines Flight 19.pdf/48

 down, unless the turns had been extended into complete circles, since the airplane struck the ground substantially on a direct prolongation of the line of flight that it appears to have been following immediately before entering the storm.

In considering the implications of this and other possible flight paths, it must be remembered that the longitudinal stability of the airplane would give it a pronounced tendency to recover from a dive, even without the intervention of the pilots. Tests and calculations on a similar airplane have shown that with the center of gravity in the position that it had at the start of this flight, and with the tab control set for the airplane to trim at cruising speed, it would require a steady push of at least 40 pounds on the control column to keep the nose from rising when a speed of 300 m.p.h had been reached. In this connection there is a possibility which is extremely remote, but may nevertheless be mentioned, in view of the difficulty of finding any combination of circumstances that seems at all probable as an explanation of the maintenance over a period of 15 seconds or more of a flight path of which the abnormality would be expected to have advertised itself to the pilots. If an airplane nosed over very abruptly and very steeply at a time when the occupants did not have their belts fastened, a number of them might have fallen or slid from their seats to the forward part of the cabin. The resultant shift of the center of gravity would make the machine trim at a considerably higher speed than that for which the tab controls were originally set, and so hold it in a dive (though probably a comparatively shallow one) if the pilots, having themselves been disabled by whatever cause produced the sudden change of course,