Page:CAB Accident Report, Pennsylvania Central Airlines Flight 19.pdf/49

 were exerting no force on the controls.

Aside from the complete disabling of the pilots or a shift of load in the airplane, two hypothetical explanations of the prolonged maintenance of a steady dive have been considered. If the pilots were blinded by a lightning flash their immediate concern would have been to avoid stalling of the airplane while their disability continued. In seeking to be perfectly safe on that point they might have over-corrected by pushing the machine into a dive, and with both pilots pushing on the control column together the force required might have been overlooked under conditions of such stress and the dive continued until the ground was reached. The other possibility considered is that the clogging of the airspeed indicator head with rain made the indicator read too low by a gradually increasing amount. The indicator would then have indicated a gradual approach to a stall which the pilot might have tried to off-set by thrusting the control column gradually forward to pick up more and more speed. This explanation does not seem at all likely to be a correct one since other instruments immediately in front of the pilot, notably the altimeter and the artificial horizon, would be supplying an obvious contradiction of the airspeed indicator's reading. Every experienced pilot would recognize the possible fallibility of airspeed indications in heavy rain or freezing weather and would check against his other instruments under such conditions.