Page:CAB Accident Report, Pennsylvania Central Airlines Flight 19.pdf/76

 The thermal effect of lightning is recognized in the electrical and radio systems of airplanes through burnt fuses, melted or destroyed wires, and other damage of a like nature, and there may be similar effects upon other parts of the airplane's structure, controls, or equipment.

Past experience has failed to reveal any case where lightning has caused the fuel of an airplane to catch fire while in flight, nor is there any record of any other serious form of fire in flight from this cause.

In this case, although all the parts of the plane were not found, those parts which usually are struck by lightning were examined, together with the remains of the electrical and radio systems. All the technicians and experts who examined the wreckage agreed that there were none of the recognized indications that lighting had struck the airplane before its crash near Lovettsville. There is no reason to believe that any usual form of lightning struck the plane or that there were any thermal effects of lightning upon the plane.

The effect is not known to have caused any injury to persons on all-metal airplanes of structure similar to the one involved in the present accident, which have been struck by lightning while in flight, nor any serious damage to the airplane itself. Mr. L. P. Harrison, United States Weather Bureau, summarized reports on a great many cases of lightning strikes on aircraft including one instance of a pilot being incapacitated because of electrical shock which was conducted to him through the mechanism of his radio headgear, but that incident involved an airplane of a very different type and it was agreed by all the experts who testified that the protection provided by the all-metal fuselage and wings and the characteristics of the electrical, radio, and other equipment would make any significant electrical shock to